I have been searching for a small folding panel for some time to take on hikes or short camping trips. I was not interested in paying top dollar for Goal Zero or similar ones and I did not want a ridiculously large panel either that would either encumber me or increase my standing for the nerd of the year award.
My other constraints were enough current to charge a tablet and mono-crystaline cells to handle shading issues better. I rated it five but 4.7 would be closer to exact since it could use a larger pocket and most importantly, a blinking light for output power since the solar angle makes a difference and a visual indicator would be helpful. It works fine as-is but these would be improvements as I see it.
I have an older Visio 8" tablet that is a power hog and takes forever to charge back up. It's battery was exhausted so I took it outside at 4PM (when this arrived), laid the panel flat on a patio table with the tablet under it (sun shielding), plugged it in and walked away. 90 minutes later I checked it out since the Sun was going over the ridge and the tablet had 36%! To me this was very impressive as it charges just like that indoors on a wall adapter. In fact, this tablet requires a high output charger to even get the Vizio back up from exhausted.
I then took it on a weekend camp with some friends. At sunrise I draped it on the side of the tent with mini bungees, plugged my S4 into it and it was charging right off the bat. My S4 went from 80%-100% in about an hour. I went on a hike and left the panel for others to use. When I returned at about noon, there was a charged iPhone, iPad, and several other phones as well as huge line of devices ready for free charging time as soon as was possible. By the end of the weekend we even had neighboring camps come over for free charging time and everyone was super impressed -- me too. I did not hike with it attached to the backpack this time, but it is small enough to do so without hanging down to your legs like another competing products.
I think that 12W is very versatile since it gives you plenty of current for a fast smart phone charge but has the ability to tackle tablets as well. I debated the smaller panel but for the small price difference, 12W is the way to go.
The price is very competitive (dollar per watt) with little competition for value. I have not had it very long so I can not comment on long term reliability yet but the construction is solid and looks like it will last. It folds down small and fits in any pack well.
I have since bought a 12000 mAh battery pack which fits in the little pocket it provides. This way, the panel can charge the battery during the sun hours and yet have power for night charges as needed too. If the pocket was a bit larger I might be able to fit a larger battery but I have not found a larger battery that fits properly. I think that having this two device approach allows for you to upgrade the pack at anytime since batteries do not last forever and tech is changing fast.
I am now looking at a panel to charge a laptop when camping (for which this can not due the the USB 5V and lack of current) but I am not planning on getting rid of this one since it can be used independently.
If it just had a larger pocket and a small blinking LED to indicate peak solar angle when generating it would be perfect. Of course I know to keep it directed to the sun for maximum output but I noticed that that concept was hard to convey to others as they thought as long as any light hitting the panels at any angle was fine.
When I'm backpacking through vast swaths in various continents, this is a handy tool to have: bright LED flashlight, and a perfectly functional USB charger for my phone or ipod, with no worries about not having power due to a lack batteries.
Even if you're not a backpacker/camper/hiker, this is almost a must-have to keep in your car or bag. Note that it is not tiny: at 6" long (including the carabiner clip) and 2 1/4 " wide, it fills the entire palm length of a 5'10" - 6" adult. But the size seems right when you hold it to press the flashlight button with your thumb, or to grip it while turning the crank. However, if you're small statured and have small hands, I can imagine it might seem a little oversized, but still importantly functional.
The crank is well designed so it doesn't hit your grip fingers when you're turning it furiously. It does make a whirring sound when cranking, so if you have sleeping campmates/dormmates, don't expect to be under the radar.
The body has a nice, almost velvety or eraser-like feel to it - good quality.