Soundwise i wouldn't worry, i don't use it myself but used it from others a few times, it sounded good to me.(edit, for twelve or serato in general, not controllers)
I'm not sure why it took so long to repair, wether it was the availabilty of the parts or 3rd party politics. But i guess a local repairshop could repair it as well, they tend to think differently sometimes and seee it as a challenge. The MPC is more a community thing, i think you can replace everything on a MPC. They were build well in terms of sustainablity, something you could service instead of throwing PCB's to the trash or whatever