Unless you intend on being very patient or go into a location where you have no access to AC power, I'm not convinced that solar chargers are worth the money. I'm military so there's been situations where we don't have access to commercial power so our criteria fits into the above conditions. However to use it day to day...
Taking an expensive battery + solar panel around to charge the iPad to full can't be very light, then solar units that can gather enough light is going to be very large when it's folded out. You could go with a smaller more compact unit but it won't likely charge the iPad to full and it's very likely to take at least twice or longer to charge. Think about how the iPad AC adapter is rated at 10watts at 2.1A, if you're going to use a solar charger I highly recommend looking at its output power specs. Most Goal0 stuff is rated at between .5A to 1A on average with maybe a few of them rated at 1.5A.
Then do you really want to keep your iPad out in the sun while it takes 8-10 hours to charge to full? It's lighter, more compact to simply take your AC charger and tap into the grid in the least time.
Taking an expensive battery + solar panel around to charge the iPad to full can't be very light, then solar units that can gather enough light is going to be very large when it's folded out. You could go with a smaller more compact unit but it won't likely charge the iPad to full and it's very likely to take at least twice or longer to charge. Think about how the iPad AC adapter is rated at 10watts at 2.1A, if you're going to use a solar charger I highly recommend looking at its output power specs. Most Goal0 stuff is rated at between .5A to 1A on average with maybe a few of them rated at 1.5A.
Then do you really want to keep your iPad out in the sun while it takes 8-10 hours to charge to full? It's lighter, more compact to simply take your AC charger and tap into the grid in the least time.