My experience from what I have owned.

TT Pro .46 = excellent, all around. Recommended.
SuperTigre .45 = better than the anemic ST .40
OS .46 AX = took OS a while, but they finally made a good .46 engine. Pricey.
Magnum XLS-52. = Eye-popping Power. Tougher to tune properly. Will dead-stick until tuned properly.
GMS 47 = Very strong engine. Known to have leaky carb (air). Tough to shut down.

Had I to purchase a new .46 engine, a TT would be at the top of my list.