Isn't the normal beam on the Luxos U the same as the B? In which case, I like my Luxos U. OTOH, it has been in a box for years now because I was afraid it would go out on me. But as I understand it, the B never had that problem.
The IQ-X is a very nice light, and usually what I recommend. I have cyo premiums on a couple of bikes and they are fairly good.