RE: 4-stroke engine for pattern
I love my 140.
Pure methanol powered happyness. I think all the problems everyone has can be attributed to low nitro content (don't be so cheap! a minimum of 15%) and old, clapped out bearings giving funny midranges.
Mine hasn't missed a beat. (truth be told it did, but I hadn't changed my needle settings in over a year of flying. go figure:P)