Ive had an OS 46ax and Super Tiger 45. OS was easy to get in the air out of the box. The ST required serious break-in on the ground, but the power was amazing.

I liked them both. If its your first engine, maybe get the OS so it doesnt become frustrating as you learn to deal with glow engines. Look in the classifieds for a lightly used engine. I recently sold my 46ax, well cared for, and lightly used for $100. Maybe you can find something similar.