WN is bad pretty much across the Northeast, it isn't just BOS. And they are poor for pretty much all transcon travelers. They are much better for very regionally limited travelers that never travel abroad. If you fly Houston to Dallas every week, they are awesome, but for anyone with a national/international mix, they don't measure up.

And, FWIW, DL isn't that great in BOS. The lack of SFO and LAX (though that is being remedied) is a big negative. B6 is much better for domestic travelers in general and I spread my travel quite broadly living here.