I have the Space Gray version with 16GB RAM and the 512 GB SSD. I'm quite happy with the purchase so far and I've already taken it on a road trip to a distant meeting today. I took it off of the charger at about 7 am this morning and after 10.5 hours It still has 68% battery life remaining.
The keyboard is nice and it's my first time experiencing the butterfly design. The screen brightness is also good. I recognize that the nits are lower than other laptops and some aren't happy with that. But for my use case, always indoors with dim light and bright lights, the screen is just fine and I don't even have it at 100% most of the time.
I do like the force touch trackpad too. Very nice to be able to click anyplace on it verses at the the bottom.
Having Touch ID and Apple Pay on here is also very awesome.
This is all an experience in comparison to my now retired 2012 15" cMBP which weighed a ton. I love how the new MBA is so small, thin and lightweight. It makes it so much better to carry around from meeting to meeting at work.
Edit: Updated info since others are asking me about it.
Fan noise:
Zero fan noise.
So far, I've heard nothing out of this machine. That includes initial setup, then doing the macOS update it needed and installing some of my apps including Evernote and downloading all the notes from the cloud and doing the initial Time Machine backup, something like 52GB in all. I have never felt it get hot yet either. That includes using this as a true laptop. What I mean by that is, I was working on my book, browsing the web and such with the MacBook Air on my lap, with a blanket between it and my legs and it never got hot, or started to overheat or made any kind of fan noise. My old MacBook Pro would always start to overheat and spin up the fans in that situation and I ended up buying a laptop holder thing to rest it on and then rest that on my lap.
I don't do any CPU intensive tasks anymore and am more of a general, everyday typical computer user, so this MacBook Air fits my bill nicely.
Keyboard
Regarding the keyboard, this is my first experience with the butterfly design and I quite like it very much. I'm not having any more typos than I get on any other type of keyboard. In fact, I feel like I'm typing even faster on this one than my old 2012 MacBook Pro or on the Apple Wireless keyboard. I know a lot of people are unhappy with this keyboard design, but many others are equally satisfied with it.
I was even doing some work last night on my book with this machine and just typing away was effortless for me and dare I say it, enjoyable.