Pros: nice looking, the propeller is protected, the clip can attach even to your hair ( you do not need a cap:) The solar panel is of good quality. It is easy to disassemble, repair it or use it for DIY projects.

Cons: The solar panel is actually 2V and the motor needs about 4V to keep you cool .So even under the strong sun it will not spin fast enough.
Propeller is lose, so it's a bit noisy. Plastic is not strong enough , but flexible.

Other Thoughts: I provide here some measurements to help you with the mods:
1) Motor consumptions at various voltages:
42mA at 4.5V
31mA at 3.6V
20mA at 2.4V
18mA at 2.2V
motor works best at 4.5-5V - best solar panel would be 5V , 50-80mA
2) Original panel
panel rated 2V, 30-50mA, normally 2.2V under strong light

Bottomline: Order one or more, you can play with it, mod it, use the parts or give it to some kid when you have enough

Pros: Essentially as described. Strong clip.

Cons: Solar cell must be in direct sunlight to work (at least start - see notes below). Indirect exposure doesn't turn the fan.
The fan doesn't move much air.
No on/off switch.

Other Thoughts: Tested with a 60 watt incandescent bulb and the solar cell puts out 1.5 volts at about an inch away. Falls to 1 volt at five inches and 1/2 volt at seven inches. The motor seems to need about 1.2 volts to start turning but will work on about 3/4 of a volt if already spinning.

Bottomline: Interesting gimmick. I bought three of these to use in an outdoor rabbit hutch. I'll probably end up hacking two together to make one that works in lower lighting conditions. I'll probably also modify the fan blades (or replace them) so they move more air.
I had one that arrived DOA so I took it apart. The solar cell works (CNSolarPower part #JGN55-P4B).