The S2 only has gear problems if you force it, but otherwise, if the camera works, there's no reason not to use it. The S2a replaced brass gears with steel and improved the overwind clutch. Classic Bronica lenses and accessories are fairly cheap, so even if you did damage the camera, you could swap the body for an S2a for not much money.
Nikkor lenses made for Bronica were excellent lenses in their day. Of course, so were Zeiss lenses for Hasselblad, and medium format gear has really come down in price in recent years. Depending on how deep your pockets are, you could get a nice two or three lens Hassy kit for not too much money, but that next somewhat unusual wide or long lens is going to be expensive. If you like something more versatile, like a 7 or 8 lens kit, those more exotic lenses aren't going to be stratospheric in price from Bronica, with the exception of a few rare long Nikkor teles.