I have been using a 10 watt setup from ICP for about 5 years now on my motorcycle. They no longer make the setup I have, the Powerfilm and Brunton roll type are similar.
I'll get to camp in the afternoon, roll out the panels and get whatever the sun has left for the day. Depending on the time of year and how high the sun is in the sky makes a difference on how useful the setup is. They do work in obscured sunlight, enough to charge the iPod or cellphone.
Rolls up pretty small and fits inside one of my Jesse side cases.
It's been through a lot of jkam abuse and still works great.
I charge my iPod, cell phone and laptop with it along with a 12v battery charger for AA/AAA batteries. It has a bunch of different connectors like battery clips, female and male cig lighter and bare wire positive/negative leads. Mine can be daisy chained together so you can expand the system by adding additional panels.
These roll up solar panels were originally designed for military use so they are plenty durable. Eventually, some of the panels will degrade in efficiency from a dying cell or bad connection.
When mine eventually fails, I'd like to replace it with the style that fold up into a book. Unfolded they make a fairly large panel and folded up would give more choice of places to store the package.
