Within in just the last few posts we've chosen UI's ranging from ones with no learning curve to ones requiring active participation by the user to even access all functions. I own lights with all of the major listed UI's and find it also enjoyable to use some of my lesser favorite UI's, and not only just to spend a bit of time with some of the other excellent lights I have, but also chosen depending on what I'm planning on doing with them on a given day.
Doesn't happen often anymore, but I'll still grab one of my Surefire's, more often than not the E1L and its perfected dual modes, and then from time to time the E2E/E1e combination, which being single mode lights just don't get any easier.
I'll always admire my Zebralights and innovative UI they've given us, especially when they also allowed us to customize high, medium and low levels on the fly, but try as I may, one of the CPF favorite UI's has kept itself mostly present in my collection as lights I like, but don't tend to carry.
It can be tempting to suggest that only flashaholics would ever be dedicated enough to internalize the Zebralight UI, but I have one friend who while not a flashholic, is a technology lover and he absolutely fell for the SC52w as his favorite and because he spent the requisite time to learn it, likes it over any other light I've shown him. Still, they do require time to teach proper command execution to the hand and I see them as a risky light to carry in any situation requiring that high never be turned on with any but the most practiced of users.
We all have to determine what light will fill the needs of the moment and the UI's I immediately reach for when going out with photographers in the dark are ones that allow no possibility of accidental high activation, meaning my good old V10R Ti, TC-R1, memory activated HDS Clicky or Rotary.
None of these UI's mentioned in the entire thread deserve the title of best for all users, but they all definitely earn the title of best for specific users, or specific usages.