The fares are sometimes cheaper; the WN effect is a bit stronger there than BOS. It's easy to search PVD as well; just check it out next time you're pricing. Florida and Philly are routinely cheaper than Logan; ATL is routinely more on DL and roughly equal on US. Remember if you dont demand a legacy carrier, WN doesnt show up on conventional booking engines, as their recent cmapy commertial sings.
Parking is vastly cheaper, though that may not affect you if you plan to take the train. There is virtually always an online coupon for garage B for 12 bucks a day.
Security is fast, and more polite in my experience. They were installing nudoscopes last time I was there, to the far right of the checkpoing. May be avoidable if you take the permier line which is to the left, but it's been a while as I fly US and have been doing the DEQM promo from Logan.