The LA series of engines are bushing engines vs FX is a Ball Bearing engine.
If you are looking to stay in the hobby I think a 46 is a good choice. If you are looking to save some money but get a good engine then I would look at a Thunder Tiger Pro 46.
I have several of these engines and they are not much more than the OS 46 LA and are BB and are much better than the LA. IMHO

Bill