When I first started I always had issues with the mydevices to the point that I wouldn't even grab one, but we got a new batch in and it's been smooth sailing ever since. I'm only on the sales floor and don't know how to pull so I don't need a pda, and when I'm stuck with one I find it annoying to carry around. The pda might be able to do more but I only know the basics. I like that the mydevice shows if something is on sale or part of a promotion (because people always ask if a certain item counts). No sign of the zebras yet here.
We do only have a limited number of mydevices though so if I can only get a pda, I end up using my phone to look things up instead of the pda