I have now used my iPad Air for some time, and it is a huge improvement over the old iPad. This almost all down to the weight and the size: having lost 180g it is now light enough to hold comfortably in your hands for a long time. Even holding it in one hand is OK, not for more than a few minutes, but when you switch hands holding it, you can easily support it. The iPad also lost some width, just enough that together with the reduced weight you can now easily type away on it while standing or walking around. It has become a much more mobile device, and I recommend you resist the temptation to use a cover, so that the extra weight does not hinder you.
The Air allows you to create a remarkable variety of output, and you should plan accordingly. Almost everyone who has a basic iPad with 16 GB has come up against capacity problems, so you need to get at least 32GB, and should go for 128GB. If money is tight, stretch your replacement cycle by a year: it is much easier to live with a somewhat slower, but still plenty fast computer for a while than to constantly bump into a capacity limit and needing to go through hoops to keep everything you want on the iPad. It is also a good idea to spring for the cellular version, having data and GPS on the go is a nice convenience.