I believe the McIntosh MC275 MKV used Shuguang Penta KT88's... not JJ's. I don't think the Gold Lion's are bad sounding in the MC275's I just preferred the crispness of the Shuguang Penta's (which I believe are no longer available). I would not let the power tube be the decision maker as to whether or not you buy the amp, as I really did like the MC275 and in many respects I with I still had it. It's well built, sounds great, dependable, easily serviced and has exceptional resale value. I highly recommend it.
What speakers would you pair it with?