One point - we got the shock mounts redesigned for the mk2 so that they pull through & fit without any glue and simply will not come undone (we've tried!). The HDD cable is now custom in the mk2 aswell - a 2-drive cable comes with all units, so user drive upgrades (out of warranty, obviously!) are just a matter of getting the right screws.
The new display board has no chips on the back of it, and the new wiring harnesses mean the drive bay has a lot more freedom to wiggle and absorb shocks. Leaving aside the bad batch of 6G drives (which would fail even if they were sat on a desk!), we've only ever had 1x4g and 1x10g fail in the field out of all the mk1's, so we're pretty happy with the mountings.
Hugo