I have both a LuxosU and a USBwerk that I can use on 2 different bikes.
I've been using the LuxosU on my rando / touring bike for day rides and running Endomondo (it uses the GPS and Bluetooth for HR). It does start and stop during a ride. Sometimes I can't really figure why it stops charging all together, but if I stop worrying about it and just let it do its thing it seems to keep the battery topped off with little loss over the length of the ride while running the apps and leaving the phone on as normal. I've even run the lights (daytime) and charged at the same time with acceptable results.

For a tour or MTB tour or long road tour out of cell range I would not be using any GPS tracking on the phone, and it would go into airplane mode, so if I did need to charge it I would be adding power and not trying to add power while using it.

I also carry a small Limefuel battery that can be charged at an outlet or on the bike. Success so far in testing seems like if I'm planning to be off the beaten path for 2-3-4 (or more) days I can certainly make due with the hub, a backup battery, etc.

I've successfully run my Garmin eTrex20 from the USBwerk while riding. It carries AAs in it, so when the power from the hub drops it switches over. This is more a bonus than something I would rely on - the AAs last plenty long enough on the road and I can find them when needed.

I have a headlight that is helmet mounted (Exposure Diablo) that I plan to charge during the day (as needed) for camp light / navigating after dark. This can charge from USB - but I have only done minimal testing with it. I can get 18-20 hours on low, so I'm comfortable that my setup will be good on an extended tour (Tour Divide, or other backcountry / overland MTB adventure) away from standard power.

Here is a switch housing I 3d printed for my Krampus. It mounts on the steerer and will house a 3 way switch that will allow me to toggle the USBwerk, my Exposure Revo (dyno light) or off. This will keep me from having to plug / unplug lights and charger. I have a bag that fits into the open spot on the Jones Loop bar that will carry my phone, helmet light, USBwerk, etc.

dyno switch housing by Mike, on Flickr

Dyno Switch Housing v1 (minuteman sent me the wrong switch so I'm hoping they ship out new ones ASAP) by Mike, on Flickr

dyno switch schematic by Mike, on Flickr