"The WiiKey has the same features as the CycloWiz, except the WiiKey is a lot smaller. The Wiikey can also be updated with a DVD. Setup Disk version 1.2 enables playing certain roms (such as SNES) and homebrew however this is achieved using the game cube compatibility mode, as well as backing up GC and Wii games onto an SD card using a Gecko adapter. WiiKey is working on close to full support for playback of backups of different regions with a few exceptions (namely, Naruto Shippūden: Gekitou Ninja Taisen EX - JAP will only work on NTSC-J Japanese Wii consoles)
Note that Wiikey can't play GameCube games with audio-Streaming (like Naruto GNT 1-4, Ikaruga, Eternal Darkness, Wave Race, and some others).
More information can be found at the official website at
www.wiikey.cn
Wikipedia.org