I don't like multiplayer achievements, generally because after a while the multiplayer is dead and you have absolutely no opportunity to unlock them if you bought the game a while after release.
BlazBlue: Calamity Trigger was particularly bad for this as the release had been pushed back so far in Europe the few players who were left were in Japan. I couldn't even manage to get the 'viewed a match online' achievement because of connection issues.
Also, after a while the online multiplayer of fighters tend to be populated with either hardcore players or people who will only spam the same move. Irritating.