OK... I did more research and the PSC has four times the memory that the SNESC and NESC have. So I would say for more demanding systems or homebrew you are going to get more mileage out of the thing than an SNESC.
I can understand the urge to keep it system specific. ( SNES on SNESC, etc). I have been debating myself on how exactly to "divy" up the different systems. Someone mentioned early an Atari 2600 USB stick.. although retroarch may not have specific support for it. It is easy enough to go into the retroarch controller configurations and create your own. What might make it tough, however, is the limited number of "buttons".. You might have to wait until they do OTG support or get yourself a powered HUB so you can have two controllers connected until you get the stick configured.
Looks to me like the PSC can probably handle up to the PSX and N64 systems ( mileage may vary on N64 ). It can easily handle the older systems .. maybe a little strain on some GBA and SNES games with a chip on the cart. Ape Escape is the only semi taxing game I've tried so far ( no slow down on the later levels like I have seen on my xbox, etc). I've yet to try games that are harder on emulation like Gran Turismo 1 & 2, Medi-Evil, Syphon Filter, Tony Hawks Pro Skater.. but when I do I'll let you guys know.
Bleemsyc 1.0 does not quite have all of the bells an whistles they initially promised.. I like to think of it as them installing the plumbing (the basic things you need), maybe a bathroom sink. But all the other appliances like a dishwasher, washer, etc have not quite been hooked up yet. The thing I like about it most is now I do not have to constantly keep on moving my USB stick back and forth to the PC. I can just FTP straight into the thing and copy files over.
One difference I have noticed over the SNESC and NESC ... is on the nintendo mini consoles they have stuff running in the background ( ftp, telnet, joystick monitoring, etc ) and I cannot help wonder if that contributes to lag. On the PSC when I load Retroarch or the built in emulator the FTP and Telnet services are stopped.
I'll post more later but that is my thoughts for now.