MANY games on PS3 / X360 were constantly diping below 30fps, and when it comes to graphics quality heavenly sworld was indeed showing what CELL was capable of. Very detalied character models (especially faces), insane amount of characters on the screen (especially during the last battle), long draw distance with beautiful vistas, and dynamic shadows everywhere. I think game was extremely impressive from technical perspective regardless of performance problems.
When it comes to Uncharted 1 I have played Crysis 1 on PC just before it (in almost max settings on 8800 Ultra), so I wasnt totally blown away with the uncharted 1 graphics like maybe PS3 players who werent gaming on PC, but considering what was available on PS3 I think uncharted 1 graphics was indeed very good (especially textures quality with specular mapping, beautiful water, and vast vegetation) and I remember many people were praising it. Below you can see for how many things Cell SPUs were used in this game:
page 35, 36, 38, 39, 49
The Technology of Uncharted: Drake’s Fortune - Download as a PDF or view online for free
www.slideshare.net
Uncharted 2/3, and especially TLOU1 looked even better, but still uncharted 1 was clearly benefiting from Cell.