So let me preface my review with this: I bought this product for prototyping a low-cost, long-endurance high altitude vehicle (weather balloon payload), to be used with the Sunny Buddy MPPT charging circuitry. As always with Sparkfun products, the customer service in purchasing and receiving the product was awesome.

However, that leaves us with the product...

1.) When I got my panels, I had to tab them to be able to make them useful. In the informative video overviewing this family of PowerFilm panels, they mentioned that for this product and the smaller cells that we would either a) use a soldering iron to remove the protective film or b) use a blade or sharp object to scrape it off. I thought that since Sparkfun mentioned this, it would be easy and harmless to the panels. When I did it, i tried both the melting and scraping method, but ultimately deicded that the scraping method was impossible without severely damaging a cell. The melting method means you have to burn the coating to reveal the tab. For me, this made the entire structure separate (the backing, the tab, and the cells). This is just poor product design. The larger panel has tabs that protrude from the structure so you don't have to damage the part that shouldn't be touched. It almost seems more worth it to buy bare silicon cells that aren't flexible and make your own panel if you have to damage your product (burning the weather proofed portion) and still have to tab it.

2) This is part is more worth a read if you don't care about damaging the coating. When I got my panels, I was stoked to start playing around with them and making prototypes. However, after burning away the coating to tab them/solder jumper wires, I wanted to measure the performance of the panels I had setup. With my multimeter I was recording that one panel produced 3.7V, and the other produced 7.2V in the same sunlit conditions. This means that the panels aren't consistent with one another in the same package grouping. For anything that requires reliable panels, I don't think I would trust these where I stand now without seeing some better manufacturer specs.

Overall, if you want these panels to just mess around with, I would consider them good, but overpriced. You can get cells on eBay in packages of 100 for $20 and make a more powerful panel for just a little more effort.

For my frustrations in getting this product setup (given the relatively high price I'm paying for them + shipping), I give it 2 stars. Would love to chat more with the Sparkfun team members that work with this product and hearing what they think about the product and any tips for better prepping my remaining panels for use without damaging them.