MLM pipes are decent, the people's pipe is really nothing super hot, but it doesnt get enough credit for being just a great, flat power delivery pipe.
I wouldn't buy any of the circuit pipes, as rheyre just re-baffled and painted tecno pipes.
I'd I were in the market for a high performance pipe, I (personally) would look to the scooter market first. But if I wanted a nice bolt-on pipe for something, I'd go Cranks Pipe over MLM.