Oddly enough, I seem to be doing a LOT better against the B-24 now than the B-17. If I can kill them, anyone can.
I agree, they are fast, they are tough, and I've always felt that bomber guns were a little too accurate and deadly for "balance'' of gameplay vs. reality.
However, I also agree that if you hit them from above and go for the wing root they'll burn like a Zeke.
The key is being patient enough to make a good attack where you hold the advantages, and not make the attack if you don't.
Just like anything else, maybe more so, if you attack without sufficient advantage, expect to fail.
I'd kill a LOT more of them if I flew a bird with cannons and was able to remain patient. As it is, with one cannon and 4 50's, and being a big target, I am far too impatient.
I don't think the B-24 qualifies as a perk plane, even though I don't REALLY like attacking bombers, and I often feel forced to defend against them and attack at a great risk, if I want to keep the FH up.