I'm currently running the HKS SSQV. I have, as some other people have reported, random venting when it shouldn't. With the SSQV there is no way to adjust when the valve releases. This apparently happens occasionally with cars running with a FMIC setup with larger piping and a MAF sensor. When around the boost threshold I can hear a faint "psss....psss...pss...pss" sound as the valve keeps opening closing. This is accompanied by some slight surging. Apparently going to speed/density eliminates this issue so until I do that I purchased a Type-S and adapter. Those should arrive later this week.

I had the Blitz SS in the past and was very happy with it. I'm not so sure I can say the same for my SSQV right now, although under WOT it works great. The Type-S is nice because it can be used to recirculate air just like a factory setup. If you're not running speed/density this is a nice feature instead of running open atmosphere.