Dave Butler wrote about PHL:
Come to think of it, I was on Angel Flight missions both times when I've
been there, so they prolly waived the fees for Angel Flight. DB

It's still a decent place. You pretty much invariably get 8/26 and 35/17
for a short uncomplicated taxi to/from Atlantic. Parking fees are a bit
weird and variable but often waived for short stays and fuel purchases,
and there is (was?) a weekend discount for fuel. (And "fill it up
tomorrow morning so I get a discount" worked fine.) Even getting in and
out when they're busy isn't hard due to the runway layout, though
Clearance Delivery can be a zoo.

With regard to the original question, despite that I live near Boston I'd
go *anywhere* before BOS, even JFK. OK, so JFK is actually pretty nice
and amazingly reasonably priced, but BOS is a pit. And an expensive pit.