I started out with an OS .46LA. I was very disappointed in it's performance. The LA series from OS is their low price line, and delivers low end performance. I now have an OS .50SX in mine. I am very happy with the way it performs. I've seen others flying with Saito .72 four strokes with good results too. The OS .46AX would be a good choice as well. I don't have experience with other brands, but would venture that a ball bearing .46 from most companies would be ok.

Scott