Re: Matt Effing Smith
McGann was the only good thing about the TV movie. His performances in the early Big Finish audios are first class and, for me, cement his position as a "real" incarnation of the Doctor. Anyone wanting to dip in should seek out the early adventures from the monthly range or the stories with Sheridan Smith as companion. A TV spinoff starring Paul McGann and Sheridan Smith could be amazing with the right production team and a willingness to diverge from Nu Who's cliches.
As for the worst, it has to be Colin Baker. Regardless of any arguments about the writing, after all Tom Baker made some truly dire episodes watchable, CB's acting and delivery was always too overblown and stagey, pulling the material down rather than lifting it. Everyone I knew *hated* his performance at the time and saying he was a victim of circumstance is a rather more recent bit of revisionism.