It depends on what your usage is. A 2010 MBP is pretty powerful and can run a lot of applications that the iPad can't run. If you don't use those applications such as Adobe CS5, iDVD, AutoCAD, Xcode, VMWare Fusion, and Toast Titanium, you're a prime candidate to use the iPad as your primary device. I would say that 95% of the time I read e-mails, read news, reply on forums, I'm on the iPad. It's just really fast and easy where the MBP or MBA would require boot up or wake from sleep and would have a few clunky apps running. Mail IMO is still pretty bad on the MBP since I still use Exchange server to get mails and there's a lack of push functionality on OSX.