My brother has a GLB, private bought not Motability. I’m not sure of the trim level but his seems well equipped, it’s a 2023 model and he usually doesn’t buy the base model.
He got it for the 7 seats so can take his grandkids out if needed, plus he wanted a SUV style car as a change from low down BMW sporty cars. It does everything he needs and no complaints so far.
The 1.3 engine does just fine, it won’t win any races but wont embarrass you either and the mpg is about average for any modern vehicle (30’s about town and 40’s on a run?) but he is a low mileage user, mostly short trips of less than 10 miles. Just drive it normally and it’ll keep up with traffic (too many on here seem to want hypercar performance with intergalactic economy 🤷♂️)
There’s nothing about it that should put you off getting one especially if you like having a badge to impress the neighbours 😂