Hi Sootchucker- I have seen your post on the BabyBMW forum- I have mentioned it on here but I went from a Mk7 Gti to a F40 M135i Xdrive.
I am really pleased with it, although I picked it up just before lockdown I have managed about 1500 essential miles and am really happy with it. Its loosening up now and feeling better as the miles go on it.
Mine is a Misano Blue with Tech pack 2 and the M pack, so 19s and obviously no adaptive,on my Golf I had 18s with no adaptive- the roads around here a pretty rubbish but I dont think it is any harsher ride in the 135, it feels a stiffer shell to me than the Golf but that's all.I doubt you would be disappointed with it.
The gearbox is similar IMO to the DSG and you have to really think about what its doing to see/feel much difference between the two.
Fuel wise I have only been getting 23ish mpg but I really have only used it for short journeys so I dont think is a real representation- my golf used to hover around 29-30ish.
The tech is great, the HUD is brilliant-the only slightly crap part for me is as an android phone user there is no Android car play (or whatever its called) but its supposedly coming via an over the air update.
The alcantara seats I love - I like these and wasn't bothered about the leather, but I got mine pre price rise and RRP was £39990 at the time as I wanted to be able to buy more coffee instead of road tax!!
I got around 17% off the RRP including the £1500 BMW contribution for the finance which I settled off after a couple of days.
Our dealer lent me a demo for the weekend- I would suggest trying to do something like this if you can. Looking at the MK8 Golf I cant see you regretting it. Good luck!