SW at Logan goes mostly to Midway and BWI direct and everything else indirect. Midway is great to have from Logan, but still cheaper at PVD for a direct fliight fare and parking within walking distance of the terminal every time I've booked.
JB is my current favorite airline, but it's not all roses. The recent reservation system change has caused havoc in making flight changes. My reservations for 2/10 to 2/17 were made in October in the old system. Both flights were cancelled due to weather in the northeast about 14 hours before the flights (and after I was checked in for both already). It took a supervisor's involvement and over an hour on the phone both times to get the new flights booked. In both cases, they couldn't give me seats as the flights were locked for airport seat assignment only from 24 hours ahead of flight time. Given they moved to AA's Sabre system, this doesn't make sense as AA can always give me seats on a re-book. Maybe it's a phased implementation and they'll add this later.
It was very helpful that JB had 5 direct roundtrips and 6 one stop in JFK roundtrips to choose from in re-booking. Casual flyers need to understand that JB has no intra-carrier agreements and in peak periods you may not get to where you want to go too quickly after a cancellation. We ended up leaving on 2/9 to replace the 2/10 flight as the school break peak period travel had no availability for a party of 2 to get from BOS to MCO until 2/12 if we didn't move up to 2/9.