Hi DrussTW.
There are quite a few things that you must consider. Ultimately, it’s down to personal preference (obviously) but here it goes :-
What useful features does your current car have? Do not go back on “useful” features you currently have, it will suck and may give you buyers remorse. E.g. if you have reverse cameras and all-round PDC currently, don’t get a car without.
Panoramic Sunroofs: This is a personal preference thing and you never know whether you like them or not until you have one. I am indifferent about them. I loved it when I had it and don’t notice it now that I don’t have it. The most useful feature is the vent function (which is equally achieved by cracking a window, as the Americans would say). If you live in a sunny, hot place, the rest of the sunroof is unusable unless you keep the blind/net closed and that is something I never got comfortable with - feels like it will tear in the wind.
Panoramic sunroofs come in handy for night drives and on gloomy/overcast days - just beautiful. Did I say I’m indifferent about them somewhere? LOL!
NB: if you do significant gravel roads, they tend to squeak here and there but are fine once you are back on tar roads. PS: costs a pretty penny to clean and lubricate at the dealership when you take the car in for a service.
Electric tow bars: I struggle to see a situation where you need your tow bar retracted (I am open for an education here). After towing, the second most useful feature of a tow bar is the “anti-fender bender” - keep it extended and it helps against a slow rolling car in traffic with a texting driver. My opinion, it doesn’t need to be electrically operated nor does it need to be removable. Bonus: I think they look fantastic on the X3.
Infotainment Screens: If you are going to have a permanent tablet stuck to your dash, it might as well be the big one. The small ones have too much bezel for no good reason.
High beam assist: This is a game changer if you do significant night driving out in open roads (no street lights). It seems gimicky when you hear about it but damn does it change your life. It’s like automatic wipers, at first you think how lazy am I to need a car to tell me it’s raining? Then it rains and you are like wow! It even knows the intensity of the rain! These high beam assist things are useful. Admittedly, it’s not a feature you get to experience daily but damn. Okay, you get the picture.
72000 km vs 57000 km: It’s hard to not think in terms of mileage especially when one car has 50% more mileage than the other but this is really not the end of the world, especially if you plan to keep the car for a long time. After a few years of ownership you won’t think about mileage. It’s the everyday things that will keep you loving the car.
Which to buy: There is an unmistakable feeling you get when you sit inside a car, especially a pre-owned one. Get inside both of them and get a feel of the car, see if it tells you anything about the previous owner, tug and pull at a few things and feel if anything seems off and then see which one moves you - welcome to cliché corner - and then buy the 72000 km one. Jokes, aside, if at the end of the day you aren’t 100% sure about either, don’t buy and keep looking. The X3 is BMWs best seller ATM and that means there will be many coming up for sale in the second hand market on a regular basis.
TLDR: if I was forced between the two and all things were equal besides spec, mileage and price, I’m taking the 72000 km one - better spec = better overall ownership experience.