I’ve had 2x MS, a M3 and now a MY.
The MS were quieter, especially suspension noise on rough surfaces, on a quiet road surface I could hear a faint whistling sound on my second MS from around the door mirror which was a little annoying, but gives an idea of the background noise. That said, on a smooth piece of quiet tarmac (the type of road surface does matter, anyone who’s driven parts of the M25 will know what I mean) the MY can also be silent. Overall, the MS was definitely quieter.
Comfort, same again, I know there’s a lot of talk about Tesla improving the MY suspension, but they did need to. There’s a rough country lane I drive and the combination of suspension and suspension noise makes you think you’re driving a transit van. That’s worst case, it’s far from like that everywhere, but it’s not something I’ve ever experienced in other cars on that bit of road.
Handing wise, the Model S is lazier and more relaxed, the steering isn’t so quick, and neither are drivers cars as such. That quick steering in the MY plus the firm suspension and I think more sensitive throttle make it feel edgier and sportier, but i recon if you timed it, the Model S will be quicker, partly as the later cars are so much quicker to accelerate.
Where the MY s ores is charging speed and efficiency. That said, ther3 have been software updates on the MS to improve so it might be closer now, but I was amazed how fast the M3 and MY added miles on a V3 charger compared to my old P90D