yes it is spendy. 350.00 a panel, and you need 6 so 2k mas o menos and you still have to build it, unless you go for one of the prebuilt kits, which I suspect is even more...
But you get alot more refrigerated space (4 inches in all 3 dimensions) and long term savings on fuel. Just depends on if you have the budget, or space for bulkier insulation.
Not for everyone, but seems like it could be an excellent option for some.
ain't what ya do, it's the way that ya do it...