I'm only 100 miles or so into ownership but thought I would post some early thoughts.
Sophisto grey Msport with black dakota and poplar grey. The car replaced an F10 535d that I was really happy with. I never had the same bond with the car as I'd had with some earlier, sportier models, but I found it just incredibly accomplished - it did everything really well. I got an F10 as a loaner while a 4-series order was rectified (it never was, so I bought the 535d) and just loved the boot space.
I used to pop the F10 into Sport mode before starting every journey but have stuck with comfort most of the time with the G31 so far. The car is clearly a step forward from the F10 and I don't regret changing for a moment, but the lack of steering feel, which I suspect is down to driving in comfort mode and the change in feel over the front end (the G31 feels much lighter) is holding me back from feeling totally enthusiastic about the change.
After finding all sorts of ways to get my golf clubs into 911's and Elise's in the past, being able to throw them into the boot and forget about them (with masses of space to spare) was my main reason for getting a grown up car. The recesses behind the F10 rear arches made the F10 capable of swallowing 3 sets of clubs easily and I had a slight doubt the G31 had the same recesses - earlier touring versions didn't. No problems, however. I liked the versatility of the touring and owned an S2 Avant years back that was really practical, so chose the G31 over the saloon. After reading and watching various reviews I specced the 'extended storage' option, thinking it bought me the sliding lashing point lugs in the boot (which it does) and the elastic storage straps in each of the wheel recesses, which it doesn't. I'll query that with the dealer - I saw them on NL spec cars and they attach to the panels covering access to the lights so would be an easy thing to add, but I'm surprised they're not included. The configurator suggests they should be included....
I've a nagging doubt about the build quality of the interior and just feel the F10 was more solid. A lot of that view was caused by driving away from the dealer looking for the switch to turn off the HUD, then finding it in the iDrive settings. I can't really defend why that disappoints me but it does! It's obviously cheaper to manufacture that way, and it's clear cars sell more on tech and comms than engineering brilliance, but I was a little surprised at the obvious cost cutting. With discounts the G30/31 are - I feel - incredible value, so I shouldn't be surprised and shouldn't complain. I've coded the Alpina dials as I feel they're just a little more interesting to look at in both sport and comfort modes, and match the blue interior lights which I previously turned off. The interior is a very nice place to be!
Stuff I would change? If the extended storage pack doesn't include the side straps, I wouldn't pay close to £300 for the moveable lashing points. They're good, but I use the car 95% of the time with a rubber mat in the boot so can't use the lashing points anyway.
I've seen today a few people commenting about the rear sun protection glass (tinted windows) and I'd also ditch them. I've not noticed an issue with vision, but feel the car just looks odd with heavier tinting from the B pillars back.
I'd recommend the MPPSK, though I've not gone above 3.5k revs yet, but I like the option of increasing the noise to make the car feel more involving. I'd stop short of claiming it's value for money before using it in anger.
I'm fascinated to put more miles on the clock and properly test the active steering and EDC. Interesting reading others' views on the adaptive drive (which I seriously considered) and 'standard' MSport suspension over the 10mm higher EDC. I read a review (not sure if it was CAR or EVO) which was very positive about the active steering but doubt it's possible to make an informed judgement without driving each option for a good few hundred miles on familiar roads. I do find the G31 a little numb (though it's early days and I've not tweaked settings to minimise it, nor pushed the car to test the handling) and am aware active steering could create an artificial feel though I'm hoping as Porsche have gotten it right for years BMW can too.
My display key lives in a drawer, I like Apple CarPlay but might change my mind if I get bored flicking from CarPlay to iDrive, and am a fan of gesture control which I use for volume, turning the display on and off (I turn it off unless I actually need it) and am thinking I can also turn the HUD on and off which I currently have on button 7.
I've not used parking assistant plus for actual parking, but like the fact that I should be able to protect my alloys! I've not driven anywhere but in town yet so can't comment on the adaptive lights, which, along with 4wd and MSport brakes, were major reasons for changing from the F10. I've not used the brakes in anger but did feel the standard items in the F10 were only just acceptable for the performance and weight of the car.