Hmm, I think it looks fairly close to the original. Jaggier and a bit washed out, but mostly faithful. Or at least I thought that was the only difference, as I started going through the pictures I noticed some textures were greatly reduced in quality, and I'd expect many effects to be removed. Also need to find out the framerate.
However, assuming a solid framerate, I'd say it's close enough that, especially if played on a bad TV, most people won't notice the difference.
It'd be different if the gamecube version was perfect, but it really wasn't. The Gamecube version could have been shaper, higher resolution, and cleaned up a bit. I'd like to see some side ot side shots though.