I'm not sure exactly how to define the upscaling performance, but I can try. Blu-rays with reps of being a bit too similar to their DVD counterparts do in fact look about the same as the BDs. Home Alone BD looks like the FF DVD. Robocop BD largely looks the same as the DVD aside from certain things in certain scenes(Murphy's bulletproof vest looking smoother and more detailed), Terminator looks slightly better, you get the idea. I'm using a 50" 720P px80U Panasonic Plasma, and I think the way DVD looks depends a lot on the TV you're using.
On my TV, whether I'm using this player or my Toshiba HD-A2 HD-DVD player, DVDs often look blurry, blocky, and washed out when compared to legit Hi-Def material that looks better then DVD quality. Some DVDs look decent like Attack of the Clones, Sith, FYEO, and V for Vendetta. The BDs for the latter two titles are still significantly better though. Something like Battle for the Planet of the Apes looks quite a bit more washed out on the '06 DVD when compared to the BD.
So, all I can really say is that the upscaling of some titles gets them real close to the DVD, and on better quality BDs, there is a much bigger difference in quality.