Hi all,
New member here, so take what I say with a large pannier full of salt! ;-)
I researched all this a couple of years ago, and like the OP was not overly impressed with the cost and bells and whistles of some of the more expensive items. I try to follow the KISS system as much as possible.
In the end I got the Cycle2Charge unit from Germany.
I didn't want a unit with a built in battery because I figured that if the battery ever failed, then my unit was useless. Furthermore, I couldn't charge it from a wall outlet if the opportunity presented itself. Finally, it was something that was always on the bike and there are times when I want my bike to look as inexpensive as possible.
For waterproofing (when not in use) I simply turn the dome covering the usb port. I like that simplicity.
I am not an expert in electronics or electricity (and nor do I wish to be), I just want something that will work. I'm sure from reading around that there are other units that are more efficient - but if I wanted to be efficient I probably wouldn't tour the way that I do. I bike slowly and like my comfort so I'm not ultralight.
My set-up is this:
Son 28 hub in 26 inch wheel. The cycle2charge unit mounted on my handlebar (size of a big bell), usb cable to my bar bag charging one of 2 small battery packs. My front light is dynamo operated (rear light is battery) which I switch off when charging.
On a daily basis this system will generate enough power to recharge my phone and Wahoo Elemnt with power over. I have tested this several times and am comfortable with it.
I'd average anything from 50km to 100 km per day, typically average speed of 18 kph.
I was pleasantly surprised that on a week long tour in the hilly border areas of Holland/Belgium/Germany in wet weather with lots of climbing (avg speed 13 kph) that this held true.
It will charge my gps/phone as I cycle, but I prefer to use the battery for safety. Varying speeds can mean the phone will start up & shut down frequently, seemingly using the power I had worked hart to put into it. In emergency, it will power my gps, but I tested out a Garmin Touring last year and it went nuts when connected. No problem with the Wahoo, although the location of the connection point (underneath) is not ideal.
I also plan to use the battery packs to charge my kindle and rechargeable batteries for my taillight, headlamp & camera.
Hope this helps
Frank