I have the Sharp version, and it works very well. Very powerful, plus I've recently started to cook vegetables using the sensor setting and that has worked as well.

What makes this MW worth $1,400?

You can get a SS Panasonic 1250 watts with stay warm for $270.

built in's are always more expensive. Some people don't want a cheap looking MW in their expensive kitchen. I'd rather stick one in a hidden spot than spend $1k on it myself.

It may look cooler in a way, but IMHO, it's not worth the price difference. I'd stick with the Sharp model - I'm going with the under cabinet mount for mine.