My 20C:
the M7C class is a great addition, on paper. Vanilla shields suck, and make no sense at all, but I'm playing XRM anyway, and they upped the shields to GJ ranges, which makes them (in my opinion/my style) the best ships around.
A Teladi Tern can dock 14 Fighters + 6x M6/TP/TS (4xM6 2xM8) with ~10K cargo, that allows it to be a mobile base of operations. It can field it's own fighter wing or two, while still keeping room for salvaged ships, even TS's!
Close to it would be a Panther, with 25 M3 docking abilities (don't know about M6/TS/M8), Phased Array Laser Cannons, PBE's, ISR's etc. and serious speed is pretty much my ideal carrier. It's fast, meaning it can retreat, small and consequently manouverable enough to evade atleast some enemy fire, and can pack a mean enough punch to be a serious competitor to most anything (incl. M2/M1).
2 of these + fighters and some corvettes and you got yourself a pocket Quick Response Fleet, able to do hit 'n runs, quickly protecting your assets (using ADS network security for example), and for a Pirate style game, are (next to a TL) the perfect homebase.
From the M7 Class, I think the M7M's are the most useless. Except for boarding those ships have no purpouse. You can get heavy missiles on other ships, make a bomber wing, which is much faster and a smaller target, thus can quicker deliver the punch and get out of dodge, while M7M's are bulky, slow and even so, can fire only a very limited amount of missiles.
Burn rubber, not your soul!