oh yes, flack beat LRM and (the now rarely seen) scout spam.
flacks are what make a fleet of aprox equeal numbers of flack and LRMs so annoying... cause you just plain dang cant counter in untill tier 5.
fighters? screwed.
LFs? screwed.
LRMS? screwed.
flack.. ya, that works... but it soo easy to counter...
bombers? only if you like 50% damage multipliers, and your carriers actually have antimatter...
scouts? lulz.
support cruisers? only at tiers at which you can already afford HCs...
that said though... HCs+ a few support cruisers will wreck a flack/lrm fleet.