Having previously had a MX before, the difference is noticeable in that it doesn't have the same spongy feel (if that makes sense) that I felt the vehicle had before. It feels as though it has evolved to be more tight, yet not overbearing.
Comfort mode is truly soft, so much so that it tends to feel floaty if you find yourself moving lanes quickly. Sport however is entirely different, it finally makes the MX feel as if it doesn't weigh was much as what it actually does, it's impressive to actually feel the difference.
To measure these together, if you felt that the previous system was a bit anemic or left you wanting more aggressiveness, sport will probably bring a smile to your face. Comfort is almost too comfortable for my taste, but my wife enjoys it which is equally important as she'll be driving this the majority of the time.
If you get the opportunity to test drive an upgraded MX, definitely do so, ride height adjustment is quicker to me it seems, but I don't have any video to prove this. I will post a video showing speed of height adjustment as a demonstration sometime over the weekend, weather permitting.