There's a big difference between a bomber with 3 guns defending it and one with 10. That is why the B26 gets used so much.
Also, as a tangent, myself and some squaddies have quite successfully defended ourselves in B-25Cs against even Me262s. I got a 262 killer making lower 6 attacks at least 3 separate occasions, and one of my squaddies got 2 in a single sortie before as well.
Other than that, there's no comparison to B-25C and Ju-87.