using my ipad pro with logitech keyboard.. really love the shortcut keys available on the keyboard..

typing experience on it is also great.. paired with magic mouse.. very good experience..

Old answer:

If you rich and has budget: go for apple keyboard 
If you low on budget: go for logitech

Both experience i really dun feel much differ actually.

Right now i'm using Logitech Keyboard K380 and Mouse M590, so far so good except not portable enuf if wan full EQ on the go 

Haha with apple magic keyboard price, you can smack a lot of logitech keyboards till rosak and replace XD

Nothing to regret. The screen is better in iPad Pro with 120hz. Camera also much better.

Also higher capacity.

iPad Air based model is cheaper but 64GB is a no for me. Too small already. If getting higher capacity, iPad Pro still a better choice.

Performance wise, nothing to worried as it is already freaking fast in 12z, even if 14 faster also can't feel. But the iPad Air without 120hz will noticeable in animation smoothness.

Just I hope that blue colour also have in iPad Pro, very nice colour. Haha.

Apple move to let iPad Air follow iPad Pro design is a great move. Finally more people can enjoy better iPad.

I was in the same situation. Couldn't find any 12.9 in store so ordered online. Then from time to time visit the local stores and one day found some in store (in my area I have a few switch stores). Proceed to cancel the online order and happily collected it from store. Normally the online order takes almost one month. One word on calling the stores, I observed sometime the staff is not best informed, or they don't bother to check in detail, and simply said not in stock. So I prefer to visit the from time to time.

Finally my Apple iPad Pro YouTube is support 4K (2160p) resolution. No HDR yet though.

If your iPad YouTube had no 2160p resolution to choose from, try change region to USA and tada the 4K resolution is appear.

Yaya. YouTube app.

Either 1440p or 2160p. I prefer 1440p.

Only use 1080p if video maximum is 1080p.
Maybe Apple/Google still not yet distribute to all user.

Also only video label 4K have it. If the video maximum is only 1080p then it won't have 2160p selection.

What are you talking?

Said only 1080p is you.

Now said 2160p also you

???