I have a toshiba 57HX81 (widescreen HD-capable RPTV). It's toshiba's top of the line. As far as how it compares to other TV's, the following statments seem to be pretty widely accepted opinions:
1. The Mits platinum and platinum plus looks as good as the toshiba with DVD and HD once the red push problem is corrected. Toshiba looks better out of the box.
2. The Mits line doubler however is not up to the standard of the toshiba which causes poor NTSC pictures with cable and/or satialite. (I don't think the toshiba's is great either)
3. The Mits Diamond series is better than the toshiba and on par with the Pioneer Elite. This series is expensive though.
Also, the Mits has upgradability through the "promise module" which guarentees it against becomming obselete through a $1000 firewire input module. This is a subject that has been hotly debated for atleast a year now and the truth is still yet to be determined.
If I had to do it all over again, I would buy the standard Pioneer. It's as good as the toshiba if not better, construction quality is top notch, has a better looking cabinet, and is significantly smaller in overall size. It's supposed to share alot of the parts as last years Elite.
All these TVs benefit from getting them ISF calibrated.
IMO, there are only 3 brands to consider: Toshiba, Mitsubishi, and Pioneer. My money went to the Toshiba, but today would go to the Pioneer non-Elite series.