We have several threads going for the various portable SNES units, but here's a quick summery:
Yobo FC-16 GO
This was the world's first commercially available SNES portable that plays the original cartridge medium. it is the only portable SNES so far to use a clamshell design to protect the screen when not in use. the dpad is a bit stiff but it's functional. It comes with two absolutely excellent 2.4Ghz wireless controllers that can only be used on the device. Battery life is around 2.5-3 hours. Plays 98% of all games without any issues. It has a rather awful composite video feed to its built in screen, but has excellent composite video output to a tv. The build in speaker can get LOUD. Although it can play Super Famicom games, it has tabs that region lock it to North American carts only unless you open the unit to remove them. It is around $60.
Check out my review here:
http://www.youtube.com/watch?v=elqLpKKWgC4
Hyperkin's Supaboy:
An SNES portable designed to look like an oversized SNES controller with the screen where the Start and Select buttons would normally be. The stock d-pad is pretty much the worst dpad I've experienced in quite a long time - it doesn't detect quick diagonal changes, making playing games like shooters or fighters impossible. Battery life is around 2.5-3 hours. Plays 98% of all games. Many of the initial units sold "accidentally" according to Hyperkin used the prototype Supaboy's motherboard, which has an annoying electric buzz from the internal speakers AND headphone jacks. The only way to eliminate this issue is to use the video output to a tv. It has a much better composite video feed to its built in screen than the FC-16 GO's, but it's composite video output to a tv is dark. The build in speaker has a maximum volume about half of what the FC-16's can get to. No tabs, it can play Super Famicom games no problem. It is around $80. Hyperkin's customer support is seemingly terrible - myself, I wet through a long process of returning my unit with the buzzing sound only for them to send me a replacement with the exact same problem. Others have reportedly been unable to contact Hyperkin for over a month. Buy with caution.
Check out my review here:
http://www.youtube.com/watch?v=RAxAu6kx7Zg
RetroDuo Portable
Only announced AFTER Hyperkin's Supaboy was released, this unit promises 6-8 hours battery life, contrast control and will come with two cool-looking third party controllers, which may be excellent or shit - we don't know yet. Unlike the Supaboy it doesn't have two large SNES controller sockets built in, but it does come with a dongle that allows you to use any SNES controller you already have. The gimmick of the system is that it's also got an NOAC and a cartridge adapter to allow it to play NES games as well as SNES games. It is $90.
When I get mine, I will be sure to review it.
PokeFami DX
This is a East Asia exclusive import. The signs point that it's the Asian equivalent to the RetroDuo Portable minus the NOAC and NES support. Digitalpress member Nullsilver owns one, so you can check out his full review here:
http://www.youtube.com/watch?v=qH03iZMtHxg