I started out playing pot limit almost exclusivly because i thought it would help me to learn to play better. I still go back from time to time (i even sometimes warm up there to get my mind focused)
Problem is as already mentioned that top pairs and sets are badly devalued. If you raise preflop with AA you get a table of callers with all sorts of trash. Yet i think it definalty helped me when i tried to learn more about how and why people bet at certain flops and how they play draws. Im not saying by any means im an expert but it helped my understanding of betting, flop textures and the things that begin to make you think about the game and not just the cards you are dealt.
I found also it was a good place to learn positional play without it costing you dear, but the real money is to be made in nl imo.