5 VDC at 350 mA? Colour me skeptical. I'm not sure how many phones will even start charging at that low output. My Samsung Galaxy Ace and my wife's LG Google Nexus need a minimum 5VDC @ 700 mA for example, and I believe iPhones need a higher voltage.

It is enough juice to trickle charge a few small NiMH cells though.

Based on my ongoing experiments, the only practical setup is a PV panel that charges a battery pack, which then charges the external device.

Note that the reviewer in the link hasn't even tried it out. Sheesh.