I went from a 2012 retina macbook pro to a maxed out (except storage) 14" M1 Max. The performance difference keeps blowing my mind on a daily basis. One Android project I sometimes work on took ~45 minutes for a release build on the old one but only 11 on the new one — and as it turns out I had spotlight indexing stuff in the background the whole time, and the SDK is still x86 so it runs through emulation. Fans do spin up sometimes but you have to try really hard to make it happen. On the old macbook the fans were spinning literally all the time and the CPU temperature has never fallen below around 60° on idle. That part of the case above the keyboard was always hot to the touch, on the M1 it's barely warm.