I've had my dynohub system since about 2012 if memory serves.

I use a Son28, Edelux 1 headlight and standard E-werk and seperate cache battery.

Apart from replacing the cache battery every three or so years, its been trouble free with the only maintenance being a yearly inspection of the various terminals inspection and clean.

I'd point out that the Usb-werk has an internal battery that I wonder how you replace when it goes kaput.

Locally in Australia I've met 4 riders who've all had trouble with the Luxos headlight and read of more in the various forums I read, so I'd suggest wariness.

I look upon my system as a fit and forget for the most part and after some experimentation I now tend to charge a storage battery which I then use to charge my various devices.

I have a Garmin watch, Edge 1030 with external battery and Petzl headlight torch that I can keep charged on tour as well as an iPhone.

I've been so happy with my system that I've mirror'd said system on my Extrawheel bike trailer.

Edit: I've just remembered that my E-werk is a bit older than I stated due to it coming off my previous bike.

The dynohub though is the newer kit due to my Ogre having disk breaks which the Moulton not having.

I'd foolishly skimped on a non disk hub not considering that I might upgrade the bike.

The E-werks longevity has been great and I'm very pleased with my investment.