I have the previous one. It felt much faster than the one the preceded it, and feels great under iOS 7. The Air in store feels faster but I personally feel it's more subtle, whereas the benchmarks say quite the opposite. The most noticeable difference is the feel and (less) weight. If you've used a iPad mini, it's just more of the same - just bigger
The lightening connector uses a lot less real estate (more important on the iPhones) but is less fiddly to hook up and actually feels a more robust connector.