Well, right now my netbook does not get a lot of use as it does not do anything that i want to do that I cannot do on my iPad. So for me it will have to run SAS and the windows version of Excel. So far, the net books I have tried are a massive pile of fail with SAS. They will run them, but it is not a pleasant experience. In fact, running it on the desktop over VNC on the iPad is much superior. I would not use even a 13" notebook in this capacity as I have one and it is relegated to desktop duty. Now the netbooks run straight Excel fine, but when I put in the add-ins that make it useful the experience drops way down.
In using Apple computers they have provided a more transparent platform for my software. I spend a lot less time managing the OS and hardware on the Macs. In my old age, having more time to do actual work, rather than maintenance, is very important. That has been the reason I gave up on Linux a long time ago. Very personal and probably not mainstream reasons.
The legal thing is also becoming an issue at the University and I definitely need it to hook into the network. I also may buy it off of a grant and then the legal issue is a current issue trying to run OSx, as Dan said above.