I couldn't resist the temptation and installed iOS 11 beta 1 on the iPad - I'll wait for the public beta to upgrade my phone.
First impressions are good.
Drag & drop is going to be very handy and may actually make me use the iPad more than I do. As it's an Air 2 I only seem to be able to drag one thing at a time rather than gathering a few items together at once as in the demo - that is presumably reserved for the iPad Pros.
The new on-screen keyboard is very nice, being able to type numbers and punctuation by just dragging down slightly on a letter is great but it makes you wonder why they didn't also add dragging up to capitalise.