I voted Supercard it has 1 feature I love because I make my own cheats.. and Real time!!! fully changeble cheats are wicked
anyway the SC has..
Tripple Boot option for 3 Firmwares.. SC,DSTT,Yasu
Switching from one OS to another instantly or choose at boot-up by holding x or y
Multi save slots
Very quick game fixes (even still do this for their slot2 range)
RealTimeSave
RealTimeBook/Guide
RealTime Cheat Engine