While we won't know until someone actually bites the bullet and buys one of these things, I suspect it will actually be a downgrade from what you get with most TVs.
Getting a good picture from something composite on a LCD is really hard, but the best way to start is with the RGB signal if you can. The TG/PCE already muxes a RGB signal into a composite one, then this thing is going to digitally convert it back to RGB internally in order to display the picture. That's a lot of conversion for nothing.
Someone pointed out an eBay RGB to component converter that was cheaper and almost certainly yields better results. You'll need an RGB mod first though, of course. He seemed to really like it.
Speaking of this problem, I wonder what the laserdisc people are doing? LD is natively composite, after all, and still has plenty of irrational hardcore enthusiasts. What are they doing?