I own the OEM version (same as the retail but does not include games) of the Hercules 3D Prophet 4500, and the visual quality is outstanding. Here's a run-down of what I have and how it works:
On my Philips 107S 17" monitor, the picture is razor sharp at 1280x1024x32. I have no blurry pictures, no scrolling problems, and no distortion whatsoever in 2D.
With my AOpen 12X DVD-ROM drive, every DVD movie (including high-speed action movies like Mission Impossible 2) has played fine. To me, the picture looks as good as many home DVD players that I've seen. There have been no skips, no missing images or pixels, nothing to complain about.
Playing Diablo II, Unreal Tournament, Myth II, Quake III, and Starcraft everything runs fine. I mainly play in Direct3D, so maybe someone else can comment more on OpenGL quality. I did have to apply the latest patch to Diablo II to get it to run past the introduction, apparently it's a problem with all 64MB graphics cards. But visual quality is again outstanding. I get roughly 60-70fps average in Unreal Tournament at 1024x768x32 with 8 players total.
If you have any other questions, or want me to run any other tests for you to encourage you to buy this card, just let me know! All in all, the Kyro II is a great card for the money ($112 at newegg.com last time I checked). I have had no problems (with the exception of the Diablo II patch) with this card in every application and game I have tested.
Nick