Re: Never used an Ipad before, but want IPad Air. Will this be complicated for me?
A smartphone and a tablet are similar devices but not identical. If you are using an iPhone already, a lot of stuff will be really familiar to you. If you are using a smartphone with a different OS, you'll still get how everything works (touch interface is similar, gestures are similar, etc.) but you'll have access to a different platform with different apps.
One nice thing is that a lot of major third party apps are cross-platform (on Android and iOS) and often new apps appear on iOS before they appear on Android.
Definitely go to a store and check them out (to be honest, you don't even have to demo an iPad, check out some Android tablets at Best Buy, Walmart, etc.) to get a feel for the size of the display. I vastly prefer my iPad for web browsing, watching video, and doing work (document editing, etc.) The larger screen is a real asset. The other nice thing is that if you're on the road, you can conserve your phone's battery by working on your tablet.
Depending on what you want out of your tablet and what you are expecting, an iPad Air could be a great buy or it could be a very expensive investment on something that isn't a sure thing.