As a film/video producer director, there is no such thing as too large a screen. i have a full-size iPad and love it. My wife has a mini, and while it's okay and, since it's on the same account, it has all the same apps as mine, i dont much like using it.
And if you do get an iPad, regardless of the size, make sure you get the wifi/cellular model. It has a stand-alone GPS/Glonas reciever in it. The wiffi only model does not, which means you have to have connectivity in order to plot your position. With my iPad II wifi/cellular, I can find and track my position on a road map app, or on a marine chart using Navimatics, with no connectivity at all. I have used it in China, the Middle East, Malaysia, France, and many more places to find out where we were or how to get to where we wanted to be, witn no connectivity whatsoever. Wifi off and celluar off.
We use the iPad with the Navimatics app on our boat as a "big picture" device, zooming in and out or panning around the charts with just a few finger swipes. Navimatics also has Active Captain on it, so there is a ton of information available at the tap of the screen And since we have the wifi/cellular model (both my iPad II and my wife's newer Mini) we can do this out on the water with no phone signal, no wifi signal, nothing.
This is impossible to do with the wifi only model. So even if you don't have or want a cellular account, if you have the cellular model iPad, you can take advantagea of the built in GPS/Glonas receiver in this same way.
It's amazing how many clerks in the electronic stores don't have a clue about this difference in capabilities. It's listed in the iPad specs on the Apple site, but you have to drill down quite a bit to find it.