Seconding the opinion that they are more alike than similar. Brunswick, Maine has great public transportation (bus and train) options to Boston. Portland is a small city but a city nonetheless. So a finger on the scale for access to a bigger city if that matters. Really, at either of these schools, there’s so much to do on campus that accessibility to other places should not influence much.
Amherst has more students owing to the 5 colleges.
Both are NESCAC schools and probably have similar travel for your sport. The Maine schools have a lot of fun with the BBC rivalry.
You may also want to go through the exercise of planning out your 4 years in your planned major, taking into account distribution requirements, study abroad, etc and see if there are meaningful differences.
There is good skiing in Maine, but you’ll need a little road trip to get to it. I’d choose Bowdoin, but that is only personal preference. Maine is a really special state, and getting a chance to live there is pretty great. But then again, I’d be pretty excited to live in Hawaii too!
You really can’t go wrong on this one. Both are excellent, well-resourced institutions in beautiful settings.