Yes on balance, you have made the correct choice but don't fully dismiss the Bandai though. Not up to Tamiya quality but they do build into a nice model if you are prepared to work on them a bit. I have a Stug iv which I run quite a lot on it 's original gearboxes which are a bit noisy, but the slow speed control is terrific. The main problem with them is the output shaft gear spins freely on it's shaft after a while and drive is lost. I bonded mine with Loctite 638 and have no problems on that score. I have converted mine to airsoft with gun traverse and recoil using a clark TK22 control PCB. I too will be keeping mine. Enjoy the Sherman - it's a great kit.
Cheers
CaptB