Those with which he replaces the standard sound for one phrase in Arched Maid Via RDJ; specifically, how precisely the sound and its tuning resonates with the emotion of the song in the slow version, but not in the fast.
Aside from this ineffable resonance, I prefer the faster version in every way; but this brief phrase is so integral to the perception of the rest of the song, it outweighs all the added intrigue of the faster drums, making me prefer the slower version overall
For comparison (Set to play a little before the phrase to add context):
Fast - http://www.youtube.com/watch?v=IpSdQpSmg6s#t=86s
Slow - http://www.youtube.com/watch?v=-pzTGolXgS0#t=91s
Just one of those moments that reminds you of your humanity; how easily emotion can override the "oh, that's really clever"-ness.