Both Gray and dcolbert above point out that they want a single device that can do everything they need. As yet, no one device really meets those needs, though the Surface tablets and the iPad come close--with Android carrying a couple of different advantages. Still, if they don't have the battery life, would any of them truly meet mobility needs?

A small anecdote:
I write fiction and do private tech consulting for income. I use an iPad whenever I'm not at home. This past Wednesday, I had to take my wife to the doctor's for a followup after cancer surgery (no, I'm not asking for condolences or pity, just making a point). My iPad was fully charged and by the time my wife came out I'd used about 10% of that battery. On returning home, I accidentally left the iPad in my car--where it remained for 48 hours in temperatures that went from near-70 degrees on Wednesday to 26 degrees on Thursday night. When I retrieved the iPad from the car, the battery still read 89% despite the 36 hours off of a charger and sitting in sub-freezing temperatures for a minimum of 16 hours. Please note that this is a first-generation, 3G model, not one of the 'latest and greatest' with the newest battery technologies.

With this, I personally feel that the iPad is still the best all-around product for productivity and entertainment in a mobile device--despite the other platforms' other advantages. The Surface RT is, to me the best non-Apple device despite its other limitations while honestly Android for now seems to be the better productivity platform--on a hybrid device like the ASUS Transformer. Microsoft has the concept down, but doesn't yet have the execution. Android lacks the concept and the execution of integration while iOS lacks the concept but succeeds with the execution as far as it goes (based on this article Apple's integration and automatic synchronization of data is still better, though it doesn't run desktop apps themselves.) Use what you like; hate what you will; no one product will meet everybody's needs or desires.