I see the rah rah brigade is out for the Abbai. I'd not be snide but since those of us whose groups' actually find them weak are whiners, I guess I should say something equally derogatory about the kiss ass brigade.
Our group has found Burger to be closer to correct than the rest. They can be tough if your opponents don't allocate their fire well and manipulate range well, but most folks seem able to figure them out after a try or two and spank them around, though the games do tend to be longer.
Tiraca - star of the fleet, great ship
Brisaria - good ship, one or two in larger fights is enough
Shyarie - tougher to use due to lack of Stealth, but fun in larger fights
Milani - great little ship, but the weak kotha makes it feel you don't quite get your money
Marata - just lacks punch, especially with the current beam rules
Bimith - decent ship once P&P comes out
Lakara - tends to struggle to get it's beam to bear, and rarely gets to fire it's other guns at all
Juyaca - strong ship, held back by slowness. Typically disabled by a couple of turns of beam fire from equivalent ships, so only a turn or two of fire.
Brivioki - nasty weapons suite, no real complains here, though the kotha could suck less of course.
So, they can make a very strong swarm fleet, with the medium/larger builds suffering more than usually vs fleets that out sink them, due to limited threat sphere. Once you get to Arm. ships they do well again as the range opens up and they get a good threat sphere again.
Kotha are best used as a AF extension platform for you escorts. It fixes your dogfight score issue, as each fighter gets AF dice.
Table size matters a lot with this fleet, as does terrain density. If you can space yourself well you can get a good strike in, but the attack then run to regen never seems to work on anything but a Tiraca here or there.
Ripple