For $20 I really like this new Matone dual USB battery pack! I haven't found anything better at this price.
At 10000 mAh advertised, I can get around 1 3/4ths full charges on my iPhone 6 with this battery. It seems a bit low, but is certainly enough juice for my needs. Keeping a cellphone running Waze going on an all day motorcycle trip. Charging with the solar panel is slow as there isn't a lot of surface area. I'd consider solar to be an emergency only kinda thing, and not to rely on it for regular charging.
This'll certainly be the battery I use for this Spring's road trips.