I'll double check, but I think my mash unit is 1500 watts (~10 yrs old). For a typical 5 gal batch I can ramp at about 1.5 F per minute (3-3.5 gal H2O, 6-9 lbs of grain). What I really like is that I can use the foilized bubble wrap for insulation with no fire/melting issues. I did spring for a nice magnetic SS pot. I made a custom insulated lid. My sparge water (5 gal) easily heats to 170 F in the time it takes for me to do my mash (includes weighing and milling times)
Of course then there is the bonus that you can use the cooker for cooking food. I have a two-tier system and use gravity to move the sparge water. My setup does provide quite a bit of flexibility as far as arrangement goes, is easy to set up and would lend itself well to a small apartment. Mine lives in the basement and is almost always set up though.
I've thought about hooking it up to a temp. controller to do automated step mashes (would need an auto-stirrer then too), but that would only allow me to turn it off after a set temp. was reached. I'd have to patch into the control board to really do it right, and I'm not prepared to do that to my cooker - yet