A high maxfps is not really that great. Varying between 100-400 is probably actually worse than a constant 90, and if it goes too high you start running into the problems that occur when you're sending 4 or 5 frames of data every server frame (MAX_PACKET_USERCMDS anyone?)
The default value is usually enough for most people.
edit: I'd like to notify the reader of the nonzero probability that I am talking out of my arse. I apologise in advance if this is the case.