Often times, spec bumps between hardware revisions can offer theoretical improvements that are often hard to see. I got my new black SS series 3 yesterday and replaced my black SS series 0 with it. Today, there were at least two obvious benefits in performance over the series 0 that have made me quite happy. ApplePay through the watch is, wait for it, snappier. Very quick, nice, sharp haptic response. It turned the transaction from a 'ok, let me wait for this to go through' to an effectively instant gratifying snap on my wrist. The first time I used it today, it actually caused me to comment out loud. Unlocking my 5k iMac with my watch is much faster. I was really hoping this was going to be the case, that the often slow unlock speeds through my series 0 watch was gated largely by the watch, and not by the bluetooth on the iMac. Turns out, a fair amount of the unlock lag was from the series 0 watch. It's not an instant unlock, but it is very much faster and consistently so (I'm guessing about 1.5 seconds?). Definite quality of life improvement. So far, I've been very happy with my Series 3.