Welcome to the hobby Doug! What Spaceclam said is especially true. "Best" is very subjective here, as u will see in the other threads. Every one has a personal preference and an opinion. To be politically correct, my "personal" preference would be the OS46FX or AX that u mentioned. I've been using OS engines since I was a kid, racing 1/8 scale buggies, and they have proven to be very reliable. The OS46FX is rated at 1.62HP, 0.26HP more than the OS40FX and it is slightly lighter as it is a bored-out 40FX. The 46AX (your choice) is a newer version of the FX and it has slightly more power. These engines are extremely reliable since they have 2 needles (high speed needle and mixture control) and they are ball-bearinged. What a beginner should look for is an engine that runs consistenly and reliably so that it instills confidence in flying. You do not want one that stalls when u are flying or one that requires a lot of fine-tuning. U will also want one that has ample power to keep up with your progress into basic aerobatics. The 46AX or FX wil do all these at quite a reasonable price, and it's powerful enough to be "transplanted" into your next sport plane. I have 2 of them - I've had the 1st one since I started learning and it has taken serious head-on crashes but still runs perfectly.