I have the IPAD 2 with the German made waterproof case, It cost me 350 from the Supplier in Oz but i can tell you its well worth it, The protection it offers is fantastic,
So far i have had used it as purely the GPS in the boat and what a greta thing it is, the latest update from Navionics made it even better.
Will happily not put a new GPS in the boat now, Slowly transferring all my marks over now.
Cheers Lee