Obviously every system is different, but since going up to V10 (right now release C), I've had more success than any V8 or V9 I ever used. I'm using all variations of Cineform without any problems at all.
Most of the issues with Cineform were a result of any custom Vegas v8 or v9 Cineform render templates not being imported correctly when you install Vegas v10. You can either generate new render templates or simply change the codec of each of your custom Cineform templates to something like "Uncompressed" then save it and change the codec back to Cineform and save it again. After having done this, Cineform has worked perfectly in Vegas v10 for me.
I just installed Vegas 10 and I'm using Neo HD 5 (latest version). I noticed that the export settings for Cineform from within Vegas are much more limited now. You no longer have the option for interlaced/progressive, aspect ratio, hd colorspace etc. All that is available is: Encoded format and encode quality (no higher HD setting).
Is this normal for Vegas 10 due to the changes in the sdk or has Sony not completed the features?
Vegas is now using the Cineform SDK which means it's more tightly integrated into Vegas. You can set the options for interlaced/progressive and aspect ratio from within Vegas itself. As for color space, Cineform will just encode what it is given. Technically, Vegas operates in RGB, not YUV and I'm not completely certain what the implications are for color space. I'll investigate.
Nevertheless, according to Cineform, Sony has not fully implemented all the features available in the Cineform SDK. Perhaps David Newman, the chief technical officer for Cineform will chime in about this, he is a frequent contributor to this forum.
As John Cline said you need to be careful with templates. Vegas Pro 9 and 10 share the same templates but NOT the same CineForm implementation!!! This is critical to understand if you jump between VP9 and VP10. You should recreate your CineForm templates in Vegas Pro 10 and put "(v10)" in the template name so you know not to use this template in VP9. If you don't use VP9 anymore than there is no need to name them different but you do need to select the correct codec in VP10 and press the Customize button and configure it for your needs before saving the template. This part is critical.
I had hell with v8 and cineform, but since moving to 10c things have hugely improved. I tend to use the default setups and options and these are all going perfectly for me at the moment outputting for PAL widescreen TV and hidef mp4 web.