I am just going to point out the B'rel pays for its enhanced Battlecloak with less hull, its not much of a question of being "overrated" but rather why grip yourself with a DHC B'rel when Hegh'ta can do about the same with 3k more hull to spare?
I imagine someone might argue that hte B'rel's turn rate being better than the Heggie might provide some motivation to try this, and to be honest, it's not as bad as trying to use a Ki'Tang in L50 play. In end-use terms, however, the B'rel really only works with a Sci, where you can make use of Science abiities like SNB, VM, PSW, etc. without having to wait the 20 second cooldown to recloak.
As a Tac bird, it's just not very good, nor is it much use in a PuG, and only marginal in Ker'rat, which is where you see them most often, because the B'rel really only shines as a support bird or minelayer, and mines are of limited use unless you can guarantee an enemy's going to be coming into them. (i.e. DPB+Tric mines are good for hammering Cubes or dropping in the spawn-point at Ker'rat to break up a spawncamping fedball or Klingon Gank, but not so good against players in the open...)
"when you're out of Birds of Prey, you're out of ships."
I play KDF, because being a genocidal maniac works better with Klingons, than explaining it as a member of Starfleet.