I've had the Fenix UC02 (black aluminum version) for a few months now and really like it. I attached it to my dog's leash so I always have a flashlight available on night-time walks. For me, the UC02 is a great combination of small size, bright performance and handy operation.
Prior to the UC02, I used a Streamlight Nano. The Nano is an ok light (very small and sturdy), but the light output wasn't great and replacing the 4 button cell batteries was a pain.
I tried a Nightcore Tube for a short while - it certainly is much brighter - but I just didn't like the button interface on it and the shape was awkward (for me at least).
Then came the UC02 - yes it's a bit bigger than the Streamlight Nano - but performance wise there is NO comparison. Even on the low power setting the light displayed surpasses the Nano (IMHO). On the 130lumen high setting - it just blasts away and lights up the walking path just great.
Bottom line - a great little light, nicely sized, two brightness settings and it's rechargeable too! Highly recommended!