Here’s an interesting way to test out how the Ableton Live warp modes impact the actual sound quality. Load into an audio track a clip with piano music, such as something by Franz Schubert, or any piano music is fine.
Flip between the warp modes. Observe how each mode colorizes the sound. Re-pitch, no granular synthesis, clean, is the best, of course. But it still sounded thin for me. Complex mode is getting there, but it has a small impact compared with the original sound.
Now, think then when you add lots and lots of clips, especially with the modes that colorize the sound clips, and you get this accumulated effect of sound colorization.
I really hope Ableton Live 7.0 has a really good warp mode that avoids a lot of the current colorization of sound. Meanwhile best to Use Logic and similar tools for high-end quality productions, unfortunately. But for wild remix projects, Live is fine, especially if the output will end up as a compressed lossy MP3 file.