Thanks ushere, I have a 27" LG IPS myslf, might be a good idea to first get the most out of it with a spyder.

I own CS240. It is a wide gamut monitor. If you produce 8-bit video you will probably not use all the possibilities of this monitor. You can also check CS230. It is sRGB monitor and will cover 99% of rec. 709 gamut. However if you can spend more money, CS240 IMHO will be a better choise.
For me the biggest advantage of this monitor is a high frequency LED light flickering. It means that if you dim the monitor , you will probably not see any flickering, which may be visible in cheaper monitors.

It has a decent wide gamut IPS display. The biggest advantage for you will be a full 8 bit matrix without FRC in sRGB mode (simply without flickering in some colors.
It is factory calibrated monitor for sRGB and you will probably use it for 99% of the time.
The next advantage is that you can easly calibrate it for desired color space using free software color navigator. So you can choose for example rec. 709 colorspace and emualte it.
To calibrate this monitor you will need a rather decent calibrator. I own Spyder 4 pro and it does not calibrate well darker tones. For example sRGB calibration with Spyder is significantly worse than the factory settings. I have heard that I1 display pro is the minimum for good calibration.
The disadvantage of this monitor and almost all monitors with IPS display is that it doesn't display absolute black tones. But this is normal in IPS and this is not a problem for me. More expensive monitors have polarization film that makes the blacks more black.

To test you current monitor I recommend you to use those test charts (don't display it on the webbrowser - download on your comp, display it 1:1)

Grayscale test - shows how greyscale tones are reproduced by your monitor (the more smooth, the better):
Grayscale
FRC test - on a 6 bit panels these images will probably flicker:
FRC test 1
FRC test 2
And the finally the gamma tester. If the gamma characteristic of your monitor is 2,2 you will see two grascale tones. Otherwise you will see color strips.
Gamma test

All these test charsts my CS240 displays correctly. However after calibrating it with my Spyder 4 Pro, the greyscale test was chopped, so I returned to the factory settings.

After some time the IPS display will change its characteristic and you will probably need to buy or borrow a good calibrator.

Thanks a lot Peter!
f.w.i.w. I ordered the Spyder 4, but not the pro but the elite version, which is supposed to be suitable for video and rec709 colorspace, whereas the 4 pro won't do that and is geared towards photo editing only..

Spyder 4 Elite differs only with software. The colorimetric sensor is exactly the same. I hope your copy will be better than mine. In the future I will probably buy I1 display pro (https://www.xrite.com/i1display-pro).

However if you use Vegas pro without a video card, you will not need other colorspace than sRGB.
If you want to display rec.709 colorspace, you will have to send it to your monitor from a video card. AFAIK the ordinary graphic card is not able to do it.

So reassuming, I use CS240 with sRGB colorspace factory settings. I use as a secondary monitor for preview. In a few months, when colors may drift slightly, I will probably buy a decent calibrator.

I got my spider 4 elite today and did the calibration. the result was awful - a strong yellow tint and muddy greys -the before / after picture at the end of the procedure was almost funny, as the before actually looked perfect.
Back to factory settings instantly and the spyder is on its way back. So I guess that was that.
As to your test images, the grayscale nis not super smooth on my LG IPS 277, but kinda. It does not flicker, but I see color stripes on the gamma test no matter how i set my gamma directly in my monitor.( 4 presets only )
I then tried in the AMD Catalyst Control center, set video gamma to 2.2, but still see color stripes.

There are two kinds of calibration. Monitor hardware calibration and monitor profiling.
The first one can be done on a decent graphic monitor. Such monitor has its own LUT table which is corrected after calibration. Professional monitors are often calibrated in factory with use of very expensive and accurate hardware, so it is hard to perform better calibration than the factory one. The hardware calibration is required only if you want to change the colorspace of the monitor or if the monitor changer its characteristic in time. To perform the hardware calibration, the calibrator has to be supported by monitor calibration software.

The second kind of calibration is profiling. It does not correct the monitor settings, but the graphic card settings. The profiling generally gives you not as good results as hardware calibration mentioned above. Why? Because it may trim the color range of displayed image. For example if the calibration detects that your monitor has a red tint, it will trim the red signal. It will just say to the graphic card that the total white light should contain 240 of red , 255 of green and 255 of blue. Then after the calibration the white should not contain any tint, but the grayscale test may be more chopped, because the monitor will display only 240 steps of red instead of 255.

In my opinion, currently there are two companies that produce monitors that fit the highest standards of hardware calibration - Eizo and Nec. Other companies often advertise their monitors as professional with IPS matrix, ect., but then it turns out that the monitor hardware does not allow you to perform reliable calibration.

As to your gamma test problem - it is hard for me to tell why it does not look correctly. But it is hard to get stunning results from lower or medium range monitors.
Here is another gamma test chart.
Gamma test 2 (Download it on you PC, display in 1:1 scale, not in a webbroser).
Here gradients are created by a special combination of stripes in primary colors. The image size should be only 100%. The monitor with correct gamma characteristics of 2.20 will display a completely neutral gray in all channels. Discoloration that may occur will be the more intense, the more brightness characteristic deviates from the norm. If gamma is too high, discoloration will appear as CMY colors if too low, RGB. The dark rectangles on the right are used to assess the cut-off in the shadows. The correctly set monitor should display black and very dark gray rectangles alternatingly.

But there is also a good news for a non hiper super Hollywood profesional video editors. The perfect monitor calibration is much more neccesery for graphic/printing editing, than for video editing. Why? If you prepare a graphic that will be printed on a calibrated machine, theoretically you will know what results should you expect. For video editing you have no calibration profile of the users' TVs/monitors. Moreover some of them will display the video on a cheap laptops, others on a super OLED TV but with for example oversaturated settings.

So my advice is, if your LG monitor is facory calibrated for RGB, do not change it. Your monitor will not change its characteristic dramaticly for monts, maybe a year.
After this time you schould check if you can perform a real hardware calibration of your monitor. If yes, borrow a Xrite I1 display pro calibrator or better one (check which calibrator are supported by monitor calibration softeware). Making a calibration every few months IMHO is OK.

Peter, thanks a lot for your expertise and advice.
My current LG277 is not bad, but I just ordered the Eizo Cs240 as my main preview monitor, as the shadow crush and gamma deviations in my LG do seem a bit too far off for accurate grading and contrast /brightness corrections. As I sit quite close to in in my workspace, the 24" size also suits me better for full screen viewing, and the 27" has a lot of real estate for the timeline windows, work areas in Cubase, FX etc.

I think CS240 is a good quality/price choice. Also, using your LG as a bigger monitor for timeline in my opinion is a good decision.
We also own a sony TV for preview purposes. We tried to calibrate it with Spyder calibrator. But I would rather call it decalibration. So we decided to adjust the TV by "eyeball calibration". Eizo CS240 was a reference monitor. After adjusting many parameters, we made the TV to reproduce the colors as close to CS 240 as it was possible. Ofcourse the are not exactly the same, but the result was much better than the calibrator method.
Thanks to it we minimise the risk that the image is out of the middle of the standards and that what we see in not exactly what we really get.

unfortunately at the end of the day 'wysiwyg' applies to the monitor you're actually looking at. there's no guarantee that what your client is going to see is what you intended them to see, calibrated or not.

ushere - true, but at least I feel good about what I deliver :)

As the thread seems to be ended, let me present you a philosophical paradox - a Marilyn Monroe paradox.
If you compare adjacent cards - they look the same, but the change made many times gives you completely different result.
So let's ask ourselves if those little differences are important or does Marilyn Monroe is Margaret Thatcher? :)

Paradox