druid the 50 cals are easily the best guns in the game if you know how and when to shoot. i'd much rather have 6 or 8 50's than 4 hispanos.
at or around convergence distance, in a good tracking shot, a 1/4-1/2 second burst usually rips both wings and the tail off for me, they're deadly, you just need to learn how to use them. they aren't that great as single rounds like the cannons are, because they aren't explosive. hit with a lot of them though, and i think they do more damage on average than a 20mm burst because of the better ballistics and ROF.