I have no experience with this device, but looking at the specs, 2w output is not very much. It would take several days to charge most laptops with this.
You might be better off getting a larger, slightly more expensive panel. 6-7 Watt panels are ~$100 or so and are just as portable as the one shown. 15 Watt panels would be even better, but would be far less portable and more expensive.
It just depends on how portable it needs to be and how big your budget is.