The BD10 is a worse upconverter than the PS3. Every professional review I've read has said so. AFAIK, the only Blu-Ray players (besides the Denon's when they appear) in league with the Toshiba's in terms of upconverting are the Samsungs. However, the Samsungs can't even play many new Blu-Ray discs.
Personally, I think the Blu-Ray standalones suck at upconverting #1 to save money and #2 to make people think Blu-Ray looks so much better than upconverted DVD even on smaller displays (which it doesn't).