Went on their site but there's no graphic example of their grain plugin... is that so much different from Vegas plugin? In what aspect?

Here's my two bobs worth on film grain in DV:
Grain on film isn't a constant thing, if you look at one frame of 35mm the grain looks pretty horrid typicaly, depending on the stock and how much it was pushed. When it's projected though the grain averages out.
Now any half decent transfer from 35mm to DV really shouldn't show any grain, you've dropped the resolution so much the original grain should have been well and truly averaged out unless it was truly woeful in the original.
Also grain is the film equivalent of noise, neither of these add to image quality, with DV and mpeg compression the situation gets much worse, mpeg encoders have a hard time with either of these because it's moving over time so a large amount of available bandwidth gets used up encoding "noise", bandwidth that could be better used avoiding artifacts.

Sorry but I just find in general the whole concept a bit wierd, trying to simulate the limitations of one medium into a totaly different one stikes me as odd, I've yet to hear of a cimematographer trying to add noise in the blacks to make his movie look like video!

That's not to say that grain, scratches and flicker don't have their place in DV production, just so many peope seem to be jumping on this bandwagon I'm certain it's being grossly overused.

I think there's a whole new "look" out there. It's called, "My Version of the Film Look." Film is film. Video (in the traditional sense) is video. I remember watching TV shows when they'd simulate the "camera's perspective" of a news crew. You knew it looked different from the rest of the show, but you couldn't put your finger on it. When you saw video, you noticed the sharpness, lack of depth, etc. Film was softer, richer, warmer.

Now, with plugins, filters, 35mm adapters, "frame mode" shooting, etc., we wind up with all sorts of in-between looks. Funny thing is, the more time passes, the more people in general are accepting the "video look." Probably by the time the videographers perfect the film look, nobody will really care.

The interesting thing is that over the years film people have made attempts to make film look less like film, from memory one of the approaches was to shoot at 60 fps. Running 70 mm stock at that speed was rather expensive though.

One of the latest ideas as it use HiDef video cameras at variable frame rates, for fast action the frame rate is cranked up during shooting and projection, to get better temporal resolution.

Reminds me of some modern solid state guitar amps which have specially designed circuitry to bring back the "hum" of valve amps.

I would not do this unless absolutely necessary. On the short that I shot my DP did not notice that the camera was adding noise (which I agree looks just like grain in the video world) and I had to add grain or noise to scenes just to match the master shots.
If you're going for a film look, my opinion is that you should try everything else first before adding this. Then and only then would I play around with it and I'd get as many friends as possible to review the results. Very easy to over do this kind of thing. Of course, this is only my opinion.