Keyboard is great. I think I still prefer the chiclet keys but these are close enough. Function row is far superior to the touch bar. The touch ID button is great too. Makes using 1password much more convenient.
Small battery (which means fast charge times) and long battery life are huge for me. I've got 8 1/2 hours remaining on 91% after >1 hour of usage.
I unfortunately haven't done any local development on the machine. I ssh into a linux machine on the network. But I don't think the fans ever spin up. And it never feels hot to the touch.
I spent two weeks doing remote dev work with a 2012 Macbook Air and another week doing remote dev work with the 2020 Macbook Air. Since processing power was irrelevant my experience between the two was mixed. The 2020 Air has a better trackpad and screen. But the 2012 Air has the better keyboard. I could have used the 2012 for the rest of my life had it had a better screen.
Anyway... just some thoughts for anyone looking for a new macbook.