FWIW, I've had an opportunity to drive a few Model Y's with the new "Comfort" Suspension. I've also driven several with the "Old Suspension", and my wife's Y currently has MPP's on it. Keep in mind these are just my personal observations/opinions.
In my opinion, Tesla's new "Comfort" suspension is actually worse than the outgoing suspension. Let me explain. Tesla appears to have basically just softened the damping and spring rates. But, nothing else was changed. So, while the suspension is arguably "softer", it doesn't improve the ride quality at all. The damping is still quite bad, and now the car actually has a tendency to "bounce" over road imperfections which makes driving a rather uninspiring experience. Large road imperfections are just as bad as they have always been, with a pronounced "jarring" effect. Basically, the problem with the "Old Suspension", which was concerning ride quality over large road imperfections. potholes, or other substantial suspension travel events is still present, and now there is the compounding frustration of a floaty/bouncy effect. A bit annoying, for sure. I imagine over very smooth roads it's an improvement, but that was never really the problem to begin with. It reminds me of the BMW F30 chassis, which if you are familiar, was very floaty, and a complete departure from the previous generation E90, which I much preferred.
At the root of the suspension comfort concern lies the fact that the suspension is very much carry-over from the Model 3 which is ~400lbs lighter and had a trunk that was separated from the rest of the cabin. While there is no issue with the Model 3 suspension, it is just a pretty stiff design to begin with that transmits a fair amount of NVH into the chassis. Adding weight doesn't seem to have helped. Then, with the Model Y's large open trunk area, you get a lot more noise from the rear that reverberates through the rest of the passenger cabin area, compounding the NVH effect. I would like to stress that I actually really like the Model 3/Y suspension design overall, and it's a really enjoyable car to drive as a result, but there's no doubt that it does have more NVH than you might expect for the target market.
All of that being said, dampers/springs are only one part of the equation. I have been very happy with the MPP's on my wife's car and I feel they ride considerably better than either the old suspension or the new "Comfort" suspension. This is likely due to the fact that the dampers themselves are of significantly higher quality and have more travel. That all being said, I don't feel that they are really "softer" than Tesla's "Comfort Suspension", and I think it's an important distinction to separate stiffness and ride quality, as they do not go hand in hand. I think it's also important to understand what MPP was trying to achieve, which, as mentioned in the great post above, was not to make the Model Y ride like a Cadillac - which is likely impossible given the stiffness and NVH characteristics of all the other parts that make up the suspension/chassis of the Model Y (Control Arms, Bushings, Subframes, Ball Joints, Sound Deadening, etc). MPP achieved what I think is great Ride Quality and Sportiness, and is clearly (IMO) a much better setup than either of Tesla's iterations. To conclude, the point is that softer does not just equal better.
