I’ve now had the new Magic Keyboard attached to my iPad for a day. Lots of words have already been written about this by some very smart people. I don’t have a lot to add but a few points to reinforce:

The keyboard feels entirely like the MacBooks Pro and Air and entirely unlike the Smart Folio Keyboard. I’ve typed thousands of words with the Smart Folio Keyboard and while this new keyboard isn’t as indestructible, it feels better.
I was a bit worried about the overlap of the screen over the number row on the keyboard. That doesn’t seem to be a problem. There is, however, no way they’d get another row above the number row.
The adjustable tilt angle is great. In the past I’ve done all sorts of crazy hacks to adjust the tilt angle (including using stacks of post it notes as shims). Never again.
I’ve been happily using a mouse with the iPad a lot as I’m closing in on finishing the new Photos Field Guide. The experience of an attached trackpad to an iPad is even better. At first you’ll have to remind yourself that it’s there and shortly after you’ll wonder how you ever got by without it.
This is definitely the heaviest iPad keyboard I’ve ever used but that isn’t all negative. It feels extremely solid and there is no give in the keyboard when you’ve got it on your lap. That’s nice. Don’t kid yourself though. If you bought an iPad to avoid laptop weight, this keyboard will be to heavy for you.
With the only downside being the increased weight, there is nothing else but upside if you use an iPad with a keyboard. I doubt I’ll ever use the Smart Folio Keyboard again.