Speaking of Blu Ray compression artifacts, generally I don't notice them. Some of my Blu Rays are obvious. Especially in dark scenes or desert landscapes. I'd sacrifice extras on the same disc if it meant a higher bit rate encode to help with the compression. I have The Lord of the Rings extended editions and they spaced the movies over 2 Blu Rays. I welcomed that slight inconvenience as opposed to tons of compression artifacts.

EDIT: I'm also anxious to see if Blu Ray will become the standard format like DVD did, or if it will go the way of Laserdisc. I'm tired of buying combo packs, I usually sell my DVD and digital copies. Just give me the single disc Blu Ray for cheap