I think it a lot depends on where you locate the amps. I had a 2102 for years and never felt it increased the heat level in my sound room (14 x 20). The amp was elevated off the floor and had good circulation all around. That might be part of the reason why I never felt it made an impact on the temperature in the room---even when I stood pretty close to the amp.
BTW, I preferred the sound 2301s to the 501s on Strads both of which I heard at Stereo Warehouse in NYC a few years back. But many others simply like the 501s better. Any dealer worth its salt should let you bring the amps to your home to check it out. Alternatively, find a Mac dealer that sells Sonus Faber speakers (should not be that hard as both companies are part of Fine Sounds). Listen to the Strads or another high end Sonus speaker with Mac solid state and tubes. You will hear a fairly significant difference and will end up having a clear preference based on sound alone. Then, if you prefer tubes, you can try to make a judgment about the issue of heat which I expect to be somewhat more than I felt with my 2102. In my case, I would have put up with a little heat to get that Mac tube sound.
