Re: 57 classic and 57 plus vs. Burstbuckers 2 and 3 vs Pearly Gates and SH-5 Custom
I'm also into classic rock and blues, so for me the custom bridge is not really my style, if you'd have put a pearly gates bridge and neck option I would have chosen that one. I ended up choosing the classic 57 option (controversial I know) based on my own experiences. So much of a pickups performance depends on the base tone of the guitar it's going in, amp and playing style. I had a BB3 / BB2 set in an Epiphone and in that guitar the bridge was too harsh and the neck too muddy. Went with a pearly gates set and now it's perfectly balanced.
I have the Classic 57+ / Classic 57 set in a U.S. les Paul and in that guitar they sound great. I get woman tone and jazzy blues from the neck and some Jeff Beckish tones from the bridge with the tone rolled down a bit. However the guitar acoustically is very alive so this helps I think.
Overall for the price there are some more economical options than the Gibson pickups that will get you where you need to go, like Seth Lovers, Pearly Gates or even a basic 59 set.
What is it about the existing set that's not working for you?