I believe I know why your devices are not all showing. This is partly my fault - I made the installer automatically install 64bit version if your OS is 64bit, and 32 if you're using 32bit. What's going on here is that those devices probably don't have the 64bit filters installed, just the 32bit, so they don't all show, I believe. I'm going to have to change the installer to make 64bit/32bit an option, thank you for pointing this potential problem out.
Anyway, as for VHScreenCap, you probably don't want to use it. It's software capturing, which my app already internally supports, and can probably do much better. Main weakness with mine is that it doesn't support games that are in fullscreen mode. I would recommend using my software capture source.
Don't know about UScreenCapture though. If that's for fullscreen games, wouldn't it be better to use DXTory?