Just installed my Luxos U and have gone on a couple rides. Overall, I'm impressed. I have an Exposure Diablo MK 4 and a Lezyne MegaDrive and they make my Edelux pale in comparison (literally).

The Luxos U is a different beast:

• enough light that I no longer feel the need for a battery light
• as a geek I love that someone has finally put a bit of thought into the lights: more light close by when slow using cache battery etc.
• cache battery and bar-mounted button work great. I love ability to turn on the floods or to flash someone to get their attention.
• constant charging of the iphone. I've had Biologic, The Plug II, and at least one other charging solution (not the ework), but none worked very well for charging the iphone, mostly because they lack a cache battery and I am not fast on the uphills. The cache battery evens it out and the phone no longer goes on and off all the time.

I didn't wire in a rear light because I like blinkies. I use a Dinotte 300R.

I haven't done straight-up comparisons with the battery lights yet. I'd expect that the battery lights (especially the megadrive) will still provide more light. For me, however, the Luxos has crossed some critical threshold where it provides "enough". I was not at all comfortable riding w/ just the Edelux, but I'm fine w/ the Luxos. Rather than the Edelux being my emergency light, now the Luxos is my main light, the Diablo is the emergency light, and the MegaDrive (awesome though it is) will probably sit in my storage bin.

The Luxos is expensive, but it's a game changer. My only remaining issue is that the Luxos is on my commuter, and my touring bike is looking bare.