A lot.
1. You can scan double with the PEXHDCAP so 240p games can be turned into 640x480. Useful for youtube when it comes to upscaling to 960x720 and 60 FPS.
2. It has de-interlacing options, which is useful for PS2 games since most have interlacing. I personally like the Bob option the most.
3. You may get jailbars with SNES and Genesis games using RGB. If so, increasing the brightness to max using AmaRecTV(aka best capture software ever) gets rid of them completely.
4. While the software it comes with isn't bad, AmaRecTV is just so much better to use to see the full potential of the PEXHDCAP, along with any other capture card for that matter.
Thank you so much for this information, it's very useful for me. Now I just gotta track one of these cards down