You might consider Connected.com also. It costs a little more for a similar amount of storage and doesn't have all the bells and whistles that Xdrive has (eg, you can't make it appear as a hard drive on your computer, and the web access stinks), but in terms of backup, it works very efficiently and in particular has one feature that I find useful as a UR user...
Basically, it analyzes files at the block level and only transmits the changes. So, after the first backup of a huge UR file, subsequent backups only transmit changes to the UR file rather than the whole UR file. Handy for big Outlook .pst files also. Here is a better description:
http://onlinebackup.connected.com/
It works great for me (and no I don't have any affiliation with Connected).
Now if Kinook would develop an integrated incremental online backup feature that would keep an online UR file synchronized with a local UR file (like Connected) but also allow web access to individual UR info items, that would be cool... ah, maybe in a few years! Guess I can just use Connected and GotoMyPC in the meantime.