Things I have learned about “personal” solar panels.
Size matters.
There is no magic pill that makes smaller “low end” panels out perform larger ones (of the same technology)(see exception at end).
Buy all the watts you can afford ($ or Weight) The vaugeries of “low end” solar panels are many.
Many are made in the same factory, the similarities are not just a co-incidence.
The next step larger in the same style is the BIG BLUE 28W (5v only).
In the 28W size I did a study and more then a little research and the winner is the AUKEY 28W (has built in legs to have it stand at an angle toward the sun out on flat ground) Very Cool, followed by the RAVPOWER 24W three wire.
My definition for “low end” is that I have learned that the military “Powerfilm” type of panels are crazy expensive but they really do perform to spec. For Chinese panels assume 50% of stated spec is what you will see (on average).
So depending on the budget restrictions one may be better then the other for you. On an actual gram or sq area basis there is no comparison.
Also note that there are 12v-18v personal sized units. Obviously with the increase in voltage the amperage takes a beating. both because of the known electrical relationship but also because a 5v usb is often wired in and allocated power even when not in use. Personal solar panel controllers are just not that sophisticated to switch 100%. So before trying to “run” or even charge a “Laptop” from one, know that these variables maybe/are in play.
For laptops see the 50% rule above. Take your laptops demand and double it then look for a “laptop” solar panel at least that large (and preferable without a 5v usb outlet), to “Run” your laptop other wise all you can do is charge the battery i.e. (slow the rate of depletion).