I have an HKS SSQV, which I got off ebay from a seller in America. It was brand new and cost me about £165 including postage. Jimser also got one recently for about the same price.
They all make different sounds too, so it might be a case of trying to find someone with one and having a listen.
Tomorrow at Knockhill would be ideal as there might well be one or two subarus there []
Other good brands - Blitz, TurboXS, Turbosmart, Forge.
I wouldn't swap my HKS one for anything.