Coming from 6.1.0 without superwiping.
I have just installed 6.1.1 on my XE and immediately after getting to home screen and then checking under settings>>about phone>>Software information>>More to make sure all was well (basically to confirm 6.1.1 had registered properly - for my own satisfaction!) I long pressed the power button and rebooted the phone.
As soon as I got back to the home screen again I got a message saying the android.process.media had stopped. I ok'ed this message and then a minute later market updates began happening until a message saying android.process.market had stopped - I decided to choose "wait" and everything seemed to carry on regardless - market is working fine.
I will continue to test drive this ROM and report back as needed - If i dont post for a while it is only a testament to the stability of Mikes work