I own and use a Solio. Rather than repeating everything here I suggest you do a search on "solar chargers". There are several threads. Don't forget to set the search engine's default time frame of one week back to a couple of years.

In a nutshell, the Solio works fairly well under very limited conditions. But if your PCT trip is anything but a slow, leisurely jaunt with lots of time spent in camp I do not recommend it.