This thread sparked some curiosity so I went to the photo store today and tried out and tried out the 85L demo unit there for a good 15-20 minutes..bad mistake because, to me, I see the small difference between this and my 85 1.8. The saturation of the 85L is better, along with small amount of contrast. I've always noticed that the 1.8 has a very flat color feeling SOOC, even when compared with my sigma 35. The microcontrast that separates the subject and the OOF area is more noticeable. AF is definitely slower, almost 50mm 1.8 MKII slow but more quiet. I dont like how the 85L's red dot is very...weird and took me longer to put it on compare to other lenses haha. It's also definitely very difficult to use on moving subjects during my test of it. Overall, for me, this lens was what I expected and I will definitely save up for a purchase soon.
I wouldn't compare it to car vs car. Compare it to food, some Olive oil are more expensive than others, most people couldnt tell the difference between generic supermarket OO and imported $40 per liter OO even though theyre both just pressed oil from olives. However, to some, that small aroma, color and taste is worth that difference.
P.S. Also tried out the Sigma while I was there and the focus was off and soft off the bat. I wouldnt take a chance with that until it's compatible with the Sigma Dock.