Generally, going for provinces is not going to work very well, with the big contributing factor being that your basic province strategies are usually a lot slower when they need to get all 8 as opposed to 4 or 5, and this gives the colony-seeking player a good chance. But this is pretty board-dependent, and there are a good number of situations where going for provinces is the right thing. The issue is, usually when provinces are better, they're a little bit better, but when they're worse, they can be a LOT worse