i have flatmii 125 and wode.
Flatmii
- pros
no wait to play a game. the instant you have the iso on your computer, you can play it on your wii. no moving it to different HDD, no converting formats.
supports whatever filesystems your PC does
- cons
its windows only. technically you can write a client for any OS you want. but what little official support there is is geared only towards windows.
havent seen a single firmware update or anything since i got it
kinda slow speed. it runs at constant 2.2MiB/s. never faster, and rarely slower than that.
can't play anything but .iso ( using official software ). no .wbfs/.ciso or anything else.
WODE
- pros
play games from usb using official nintendo IOS == no "what base IOS do i need for XXXX game?" crap. you can play a .wbfs file from the system menu off a NTFS partition if you want
fast. at least 2x faster than flatmii ( havent timed it enough to say a definite number ). but in some games that have loading screens you actually want to see, you miss them because its so fast
supports a bunch of filesystems & game formats
supports multiple partitions on multiple HDDs at the same time
firmware & updates are still being actively worked on
supports homebrew
great customer suport
-cons
you have to decide between the tiny-ass joystick, a GC-mode iso, or using homebrew to pick your game.
no ext4 support ( which is a possibility in homebrew )
has built-in ripping, but it REALLY SUCKS. it extremely slow, and ive never had it rip a disc correctly for me. cleanrip is much better
doesnt really fit in the wii. i had to leave out one of the metal parts to be able to close the sucker back up
if you dont like your wii standing up sideways, you have to think creatively.