The PSB's are a better value and sound excellent. Snells are OK, they just don't suit my tastes. I've owned several pairs of PSB and they were all excellent especially at their price points. I currently have PSB Platinum M2s which I love. I picked them because they bettered many speakers that were much more expensive.
I doubt that the Snells are twice the performance. They have virtually no brick and mortar dealers so good luck seeing and hearing a pair. I'm in Boston and the only "store" that carries Snell is a TV and appliance store 40 miles west of here.