Personally I'd prefer the Defiant-R over a BoP. BoPs are lots of fun and offer a number of different game play opportunities but I'm not convinced they are over powered. Their bursty and slippery nature is made more frustrating by the sheer amount of ******** consoles and mechanics. From a PuG stand point, the most significant cause for trouble that I have with a group of BoPs is the **** poor damage that your average Fed PuG brings with them.
If Feds brought more damage, especially burst damage, instead of flooding the queues with DoT, BoPs might not be such a scary monster.
That being said, I'm convinced that there are a few players out there who are themselves overpowered. They skew any argument about the effectiveness of whatever ship they fly.