Is the M103 a keeper?

The_Chieftain:   Not at all.   I love M103, and it has my highest win rate in my garage of any tank I've played a reasonable amount bar Churchill. If you can figure out how to make the tank work, it's absolutely awesome. If you can't figure out how to M103, you'll think it's useless.   Unfortunately, the only way for OP to know if it's worthwhile keeping the tank is to play it and decide for himself if the tank works for him. Your 47% win rate in the thing indicates your play style doesn't mesh with the tank. My 61% indicates it meshes with mine. GS-G3K's about 59%, both are well above our average for heavy tanks. The only problem with the OP's position is that, as a previous poster assessed, the gun makes this tank. (In fairness, the engine helps too), and he won't know how much it works for him until he makes the decision to go with it. The saving grace is that what makes M103 work also makes T110E5 work, so it's all good training.  

The_Chieftain:     M103 is far more flexible. ST-1 is a breakthrough tank. M103 tends to prefer the indirect approach. (Note, this does not mean sitting in the rear and sniping, it means using the superior mobility and reaction times).