I use both. I use pidgin for signing in invisibly and seeing if it is worth having msn open, sending and recieving files and mmultti line input.

I use rtcomm for normal chatting as it is fast.. ii wish amsn was fast.

@general

To be fair, they both have an applet. And i cannot turn off my rtcomm one without an account disable.
Pidgin's one is quite useless imo.