Shimmer: It does crash occassionally. No specific pattern to replicate the issue. The other thing I did was turn off screen animation as it just looked a bit sluggish otherwise and when off appeared much more responsive.
I have one complaint. I HATE the remote. Its both fugly and awkward to use. The remote has been chucked at the back of the drawers and am using a spare xbox remote I had laying around.
Are you running Win7 or Win8 on your MCE box? I think the Echo had issues with Win8 but maybe they were resolved.