No UI update here in KS
The selection of which Roku 2's get the update at which time is probably a pseudo-random selection of serial numbers that aren't based on geography, at least not in pieces smaller than at the nation level.
I remember there was an upgrade a year or so ago where someone with two Roku 2's noticed that one got an update but the other said there was no update available, and it was a few days before that second Roku 2 got the update, and those Rokus were not only in the same city but also on the same internal LAN (so they appeared to be from the same IP address from outside the LAN).
There are two good reasons for pacing out the upgrades:
1. If a problem is detected before the software upgrade is fully deployed, the upgrade process can be stopped and so limit (at least to some degree) how many customers experience that problem. (Some problems just don't show up in the lab for whatever reason. For example, DHCP compatibility can't fully be tested because Roku doesn't have very model of HDTV in house.)
2. By pacing out the upgrades, the upgrade server(s) doesn't (don't) up and die under a sudden intensive load, but that load is spread out over a week or several weeks so the peak access isn't so high.
That means there are some who will get their upgrades first, some will get theirs last, and the bulk will get theirs somewhere in between.
And then there are people like me who will not get the upgrade because we are still on the Roku 1.