I did enjoy parts of McCoy's three year stint although I had given up watching by season 26. By 1989, I felt the show just looked cheap and I really struggled with the acting and writing. I just didn't believe in McCoy's Doctor and I didn't really believe in Ace either.
That said, I am pleased the show came back for Trial of a Timelord, and that it ran for a further three years after that. That were a few gems along the way.
I would say, also, that Colin's one of my favourite Doctors. Personally, I would love the show to have continued with him in the role.