Pocket Gamer has a review of the Pandora. I'm glad to see Pandora getting a bit of coverage from pretty high profile portable gaming news source. However $349 is a bit hard to justify for a portable system that is less powerful than an iPhone 4, costs as much as a netbook, and may take months to years to arrive if you preorder from the second batch right now.
If the price drops and software compatibility increases I will totally snag one of these things until then I am predicting a 3DS or PSP2 will be my next major portable gaming purchase.
Check out the review here.