The Mits is a dlp, with spinning color wheel and small potential for rainbow effects. It is also 1080p. The JVC is LCOS, 3 chip design with no spinning color wheel but is 720p which at that screen size is not going to be as good as 1080p. A third choice might be the Sony KDS60A2000 60" 1080p SXRD, another LCOS set currently priced well below the other two at least thru Friday the 25th at Sears and a few other stores.
Of the 3 the Mits will have the worst contrast ratio and hence less detail in dark areas of the picture, the Sony the best.
I have the 57732 and before I got it, we saw it at Best Buy (but it was the 57731). Trust me, get the 732 series. It is truely a beautiful TV, it has one of the best if not, the best analog and digital antenna tuner, as well as excellent picture quality. I haven't been able to see RBE or silk screen yet, and all the feeds I get in HD over air are nothing short of stunning. The only other TV I was comparing this to the other day was Pioneer's new 50" Elite for $8000.
But then again, just shop around. Buy what you like. Also note the 731 has 2 component inputs, whereas the 732 has 3.