To me most Heavies .. the Juice is not worth the squeeze. once take in to account research; advanced bases needed; etc... thean too easy to shoot down.
Was playing against a guy who rolled in a few into my territory (it was occupied so didnt really give a crap about building damage) think he might have got 1 strike off before took out two of them with air superiority fighters. then he sent in AWACS and met same fate.
To me stacking Four Strike Fighters with 1 Air Supp is a good mix giving flexibility and effectiveness. get past lvl 4 and can launch cruise missiles.
Heavy bombers are by far one of the best unit in the game, In one of my matchs a player was out of control he had a point lead of 2k but was in a coalition so he would not win. I sent in 20 bombers 2 bombers for each of his 5 main airports which bombing these locations killed off all back up leaving my units free to claim over his stolen land. The last 2 bombers stacked of 5 I used on his main cities to kill off days worth of building . After this I regrouped and blew up each one of his homeland cities tell he rage quit, little did I know he was pure airforce and airborne so he had 70+ planes stuck on the ground with over 30+ airborne stuck to. Using bombers in stacks of 5 is very painful on cities since when they have all upgrades the range is insane and they deal nearly 10 damage to buildings and they also reke a cities pop.