Ok, so the way it seems to me, the ipad opens options. You can use it with your windows or linux box running vnc. You can use it with your mac server. You can use it with amazon's cloud, you can use it with google's cloud. You can use it with apple's cloud. You have the ability to pick where your data resides, and it doesn't have to be on the device you bring with you. It's not limiting, it's freeing. Using a computer that's somewhere else means you're not tied to a location.
As to the OMG GOOGLE AND APPAL WANT MY BITS, honestly, I really don't get the objection. Instead of seeing ads about chevy malibus, I get ads for german sportswagons. Instead of getting ads about bose, I get ads about Audio Technica, etc. They don't want your specific data, individual data points are boring. Macro-data is what's interesting. The weather modelling systems don't report what the weather is like in sector (1112552124,126233623,774213266), they just use that as part of the model that says "It's gonna snow like a bitch in raleigh".