don't know about the 1250.1 as i've never used one. but the 1200.1 is great, definately worth the $. birth sheet that came with mine said a little over 1400wrms, so you get your money out of it. and i've never had a problem with it getting hot, and has never shut down on me. if you can afford it i'd buy it.
I agree too, excellent amp. Now the 1250 sx is in a class of its own, but for the same power without the bells a whistles, the KX1200 is a great value and one of the only ones 1 ohm stable. Polo..