I have the McTavish in tan and it is a great casual / business casual shoe. I wear mine with just about everything but black - they look good with blues, olives, tans, browns, and even some grays. The black McTavish would be good with jeans, but I don't wear many black shoes unless they are with a suit.
If you wear jeans a lot, either color would be good. If you don't wear jeans that often, I would suggest going with the tan.
I am curious to hear how much patina develops on the black McTavish. It looks like it has some from the factory, which makes it more interesting to me than other black shoes.