I received this item on 21 September 2011. In my opinion, this item has already paid off huge. The panel will fold compactly and is well made. I am a Corpsman in the Navy that serves with the Marine Corps, and as such, will soon deploy to Afghanistan. I was looking for a solution to power small handheld electronics, and have found it. I went to 29 Palms, California and took only the Sherpa 50 battery with me due to space constraints at the time(I didn't think it would fit at the time in my daypack). I was able to charge my cellphone and several co-workers cell phones with the battery pack. Some of the phones were an HTC smartphone as well as an I-phone. The battery pack can be charged via solar or the included AC wall adapter. I also had the Goal Zero 100 watt inverter and used it with the Sherpa 50 to recharge my Norelco razor. Upon returning home to North Carolina in early November, I pulled out the 13.5 solar panel to recharge the battery for free. It took only 1 and a half days of sunlight (remember that the angle of the sun is different in the fall) to recharge the battery to full.
Yesterday(Thanksgiving Day) I had the battery only at about 50 percent and ran, via my inverter, the living room lamp for 2 hours!! Before that I had ran my 14 watt shed lamp for about 10 minutes. So, I feel that the Sherpa 50 kit is a good deal.
One of the cons would be that the solar panel would not charge the Sherpa 50 and my cellphone at the same time; I was recharging both at 8:00 in the morning. But other than that I have no other complaints at this time with the Sherpa 50 Adventure kit.
The solar panel will still provide a charge in late evening, and I have used it through the window to charge the battery pack.
My next challenge will be to see if the solar panel can charge my 17.3 inch Toshiba Satellite computer battery. I will post an update after I try it.
And no, I do not work for Goal Zero!!