I have the LA and the FX. I also have a TT 40 pro. The TT overpowers the LA by a lot and could be compared to the FX. It has that much more power. I've had many people ask me if my plane I'm flying has a 46 fx in it and I reply, "no it's a TT 40. Lots of times they are suprised. However the 40LA was the first engine I ever bought and when choosing a reliable(I read PaPa say it was unreliable) engine for a great price for a beginner, with a trainer that is smaller than the LT-40, the 40LA is a great engine. I think it is perfect for someone who doesn't know how long they will be into RC planes or how interested they are going to be in it in the future. I have all the rest of my engines in a plane except for the 40 LA, now because of the lack of power it provides. I originally had it in an Avistar(flew great)then had it in a SuperSportster and it was underpowered. I think for the price, and quality, the 40LA can't be beat. Just my opinion, no one has to listen.