It comes in four flavors, and is in at least three Nissan cars/SUVs. The Sentra SE-R, Altima, and X-trail. I did some searches for QR on Nissan's different worldwide sites and came up with various vehicles. http://www.nissan-global.com/EN/HOME/ http://www.nissan.com.au/x-trail_full/
It is a higher tech engine than the SR20, but the lighter weight components used for efficiency make it less stout for boost. It has good torque though.
This is a good start. The qr is no sr20. The comments have been that the qr has better air flow but is weaker in the bottom end. The sr has more mods today, and time will tell on the qr.
Nice to hear from you Richard.
As for it's acceptance here in the states. The SR is king, with a strong following which it deserves. With the QR in a well built out the door suspension, the SpecV holds it's own. That's fighting words in SE-R circles. I own both an SR20 and QR25. They both do well, but the SR20 is still king. imo