Jeff I have used it for colour film and it seemed fine. The immediate problem is that you have to make up the whole kit at once and Nova gives a very short time period within which to use it all. If you have got enough films then this shouldn't be a problem. The longer term problem may be the longevity of film developed in powder. It depends on who you listen to. In terms of neg quality my prints from the negs seemed perfectly normal( no strange castes or strange and fluctuating filtrations needed) but I haven't tried to re-do any prints from the film and I cannot compare prints from negs done in the separate bleach and fix process as I have yet to try this process.
If you like to do film in 1s, 2s or 3s,(i.e. small vols) and cannot get through enough film in Nova's recommended period then there is/was the alternative of Speedibrews C41 powder kits which are good for 4-8 films per pack. Martin Reed of Silverprint used to stock it and may still do. Powder is actually quite expensive compared to say the Fuji-Hunt kit which has separate bleach and fix steps. Cheapest seems to be from Ag Photographic at 29.99 ( Matt is a subscriber here) but does 60-80 films and maybe more.
If I were solely a C41 person using exclusively colour neg and XP2 Super then this might be the way to go. MORCO does the Kodak kits albeit in large quantities but the expensive bleach should last and the fix and dev is relatively cheap and in the case of dev which has the shortest life it might be a case of being prepared to throw some away and replace.