Think I'll have to side on those who recomend the LA. Many beginers dont really know if they will stay in the sport and that will allow for a savings of $50 or so. The LA does exactly what it is marketed to do. The AX is for more performance. However, if I was to recomend a good trainer engine, I'd have to say the ST-40 for $50 is hard to beat. Duel ball bearing and TN carb. The ring engine, may resist lean runs more and cheap replacement costs. It also cheaper than the plain bushed LA. A bit heavier though. Just my $.02.