Thanks! Very helpful! Just a few more questions:
4) When using it in keyboard mode, is the lower back of the iPad exposed? Looks like it in some pictures.
The lower back is exposed in the sense that it's not directly covered by a shell like the sides are, but the leathery part at the back protects anything from actually hitting it. Testing now, I don't think anything would be likely to hit it from the sides, either. If you hold the iPad by the sides while using it in the stand position (not necessary, but you might), then yeah, your hands would be directly touching the back.
5) When using it in book mode, how comfortable and stable is it too hold in one hand? In Logitech's official pictures they always hold it in the right hand. I assume that's because it's more stable than in the left hand where you would keep pressing the keys with the back of the iPad?
It isn't the greatest when held this way, IMO. You can fold it both ways (keyboard facing outward, or inward toward the iPad) and both ways work, although if you fold it with the keyboard facing inward, the keys come in direct contact with the exposed back of the iPad, which might scratch it. Even with my previous case I pretty much always used it in the stand position so it's not an issue for me but it might be for you. Also, it would've been good if there were magnets to hold the two halves together when held that way, but there aren't so they kind of flop around. Maybe having that would cause the sleep/wake to engage at unwanted times.
Somewhat related to this but I had read some reviews saying the case put a horizontal scratch across the screen of the iPad. This hasn't happened to me and I'm not sure how it even could - when closed, the screen doesn't touch the keys and when open, nothing touches it.
6) How's the viewing angle in the lowest position? I always thought that the viewing angle with the Logitech Ultimate keyboard cover was a little too steep for lap-use.
I was actually mildly disappointed that there wasn't a steeper viewing angle because I like to have it almost vertical when I use it. However, I find the lowest position to be amicable for lap use.
7) How easy is it to remove the iPad?
I just tested this for the first time and it was easy, but I'd be hesitant to do it often just because it's metal on metal (due to the case being aluminum) and I'd be afraid it might scratch it. That's just a guess, though.
Could you put it on a (kitchen?) scale with or without the iPad? Sadly the weight data is notoriously unreliable on product pages.
I just weighed it and it came to 891g (31.4oz) with the iPad and 419g (14.8oz) without. To me, at least, that seems pretty light for the functionality of the case... I wouldn't consider it heavy at all.