I just bought one a few weeks back. It's my daily driver and the only vehicle I own. I've done very very little to it. MPG can be good as long as you keep it under 55mph (45-50 is really good). I've done 65, but it was so loud I wouldn't do it on purpose much again.
Good example of this-
From where I live to my VA hospital is about 1.5 to 2 hoursish. On the way there I burned just over half a tank hauling butt. Took less than a quarter tank coming home driving at a reasonable pace. No A/C does suck sometimes, especially down in Louisiana when it's over 100*F. However, if I'm going somewhere that requires collars and buttons, I just wear my undershirt on the way there put a dress shirt on when I arrive.
The vent is a lifesaver, even though at times you get the heat from asphalt.
One of the things I love most is that with the limitations on speed, I drive safer. Also, it's a perfect excuse not to talk on the phone and drive, because you can't talk/hear over the 6.2L anyway.
I love it, man. Best $2500 I ever spent