The pirates are probably the dominant clan, simply because they disrupt other clans so badly while keeping their own high-powered abilities. They're weak against an array of SoA, but you have to use SoA cards, not SoA CLANS, due to the pirate bonus.
A half-deck with 2-4 SoA in each half trips them up, but might struggle against other decks.
Good luck, at any rate. I still hate the Uppers more (Most broken of clans, but their teeth have been dulled by the loss of some star players), but the pirates are full of cards that are just made for headaches.
Jungo! Askai, Ongh, and Troopah!
So godly! SOB? You get one of these in your hands, you got the power and damage to take them out without needing to use the +2 life. One is temp banned? Use the other 2. 2 are temp banned? Use the one left over and make up for it with powerful 4 stars or a card like Nahema. ex for 4 stars - Greow or Scotty on SOA clan weeks. Buba for pure power. Need your own SOA? Psylo.
And Jungo got tons of good 2 stars and 3 stars to back them up as well.
Radek can bring down a majority of powerhouses. Nyema has good life gap making abilities. Hysterix can poison down to 0 making for some easy wins via life control. Boohma and Rodney for some attk manipulation and decent damage.
Meet some SOA? Ashiko. Need a Dr? Pengh. Need gap widening 2 star? Wendy. Attk manipulation 2 star? Mindy.
This is a clan with almost no weaknesses aside from the fact that you only have so few cards to choose form when making your deck. High base powers. Good abilities and almost always destined life gap creation. Get hit with a dr? You can count on +2 life. Get hit with SOA/SOB? 5 star and anti SOA cards at your disposal. Just hit them harder than they hit you. You got high damage cards anyways.
I use Piranas right now, they do pretty well. Although they do have the slight issue of no good, cheap 5* cards (I'm using Pesth right now, I'd much prefer Selma or Ahkab, or even Bloodh, though.) Their mindgames are not only fun, they're effective. In a 5-4-4-3-3-2-2-2 setup, Ahkab or Selma at 5*s gives Pill manipulation (In Ahkab's case, a dangerous fork), some decent power and great damage. At the 2 4* slots, Scubb and Raeth are great. Pill manipulation and Attack manipulation (Coleridge is a good 4* as well, nice and underrated but quite often an 8/6). For 3*s, you've got options. Taljion, Baba, Greesh, Ector, and of course Tyd, their best Waller. Now for those 3 2* slots, this is where Piranas shine. They've got some of the best fillers in the game in Hawkins (both), Tula, Puff, Spycee, even Trey and Kalder can be good.
They're by no means the best clan (I still say Roots hold that title), but they're definitely solid. And SoB messes with a lot of clans (Like Rescue. And Montana. Even Jungo.)
Wish they had a good, ELO-legal DR though.