The BB Pro used to be called the BB 5, because it has an A5 magnet instead of the A2 as in the other BB pups. It sounds a bit brighter, a bit more mid-scooped, and perhaps a little more output.
That's a good question. AFAIK, they would be similar, each with an A5, but I think the BB3 has more output than the BBP, and probably more mids as well. I think they would be close enough that the differences may be unnoticeable. But I'm no expert on Gibson pups so take my words with a grain of salt.
I like the BB 1&2 in my LP Historics, and thought they were great in the Warren Haynes Signature ES-335 I tried (and should have bought!). The BB 3 is hotter, with more mids--I like it, but to me it's not as vintage sounding as the 1&2. These three are all A2. In some guitars they will be potted, and in other guitars they won't be (and they sound different). I think all the BBVs are potted.
The BB 1&2 have more edge than '57 Classics, a little more open and not as warm. If I'm doing more rock stuff with my band, I like the BBs; if I'm doing a gig where I KNOW I'll be playing softer rock, or to older crowd, I'll use one of my guitars with '57 Classics--my LP Elegant or one of my ES-335s.
I'm sure there are people who have better ears than I at my advanced age, but I hear similarities in the BB 3, the '57 Classic Plus, and the TB-4 I have in a G&L ASAT Deluxe with 250K pots. Nice thick mids, with a bit of cut--and a tone that says, "I'm gonna ROCK!" The BB 1&2 fit more in the Seth/Antiquity camp--a very versatile pickup, usable for many genres. The BB 2s in my Historics will actually produce some twang, like a vintage Tele bridge pickup--on steroids if you will.
I'm also not a fan of the BB V (Pro). And you have to be a bit careful, as some of these are marked 1 (for neck) and 2 (for bridge), but they should have the "V" (for Alnico 5). I find them harsh, and not as sweet as the A2 versions.
Bill
Would the BB2 go well with the phat cat in the neck? Considering the phat cat is hotter then the BB2.
Depends on the guitar. In warm woods Phat Cats may not have much treble (sometimes almost none). Phat Cats don't sound like P-90's. You'll get more high end and clarity in the neck slot from a BB. In brighter woods, Phat Cats sound like a different PU.
I just read the Joe Gore review of the phat cat and he writes that its a good pickup to brighten up dark sounding guitars and the phat cat may be to bright to some users .
I saw that review too; the guy apparently didn't use the neck PU or he's on drugs. Bridge Phat Cats are bright and thin; they're EQ'd very different than the neck. Neck Phat Cats are warm, fat and rounded. In my mahogany guitars they had almost no treble. Warmer than any neck HB I've had. Way too dark for me. But that's in LP's, SG's, and 335's. They're different in bright woods, and a more viable option. The absolute last PU to use in a dark guitar is a neck Phat Cat. It may sound like it's underwater. BTW, I've owned 10 Phat Cats; took out all the A2's and gave them away to forum members. I replaced them with other alnicos, which brought the PU's to life and gave the neck models some desperately-needed high end. There's not many players that have owned more Phat Cats than I have.