I converted to SWATs last season and love them. The only draw back I would say is top end control, the '11's seems to get a bit wild when you got fairly overpowered. From the look of them and confirmed by your comments they have addressed this in the '12 model, not to mention they look a hell of a lot cooler.
Just took delivery of a '12 SWAT buts it's a 4.2 so It hasn't seen action yet. I decided to go an S1 for my biggest wave sail as I think overall it's a more controllable sail particularly in the larger sizes and a bit lighter (5.9, I use this sail for FS a lot). I'd upgrade my 4.7 and 5.2 but they aren't that old!
Personally going off even the '11 ones there is not a sail on the market that can get near the bang for your buck of a SWAT. The '12 model has stepped up in the looks/performance department but the cost still super low, maximum respect to Severne for putting out a sail like this. Personally I reckon if more people tried them they'd dominate the market, as you say I reckon they are a way better sail than almost everything else out there at basically half the price...