BWii has good online if you go on at the right time of day (or with a friend) it doesn't have enough owners for there to be lots of people online at once, so at certain times of day it can take a minute before you find anyone (and often you will end up against the same person again in the next match)
MKWii has brilliant online.
Endless Ocean is a slow game that you can only play with friends anyway, so it doesn't have any online problems other than communication issues.
I have no other online games.