Just bought one of these and I'm really impressed. Slick interface, fast enough for what I use it for (GPS - excellent performance on a number of trips recently - using copilot software, videos/music,email, etc.).
The phone features are good as well - paired with a giffgaff goodybag (unlimited texts/internet) it's fantastic - @£180 from Amazon, you can't go wrong. Planning on getting wired or wireless headphone/mic for calls if needs be - have a work phone that I use mainly, so the data access was a bigger thing for me than phone.
I have a Asus Transformer prime as well, but that's a bit too big for everyday use out and about and doesn't have the mobile access.