Well, it depends what you need it for. I actually quite liked the X4 and that 3.0-litre diesel is just an exceptional engine.

 

Here's the thing though. If you're trading out of the 428i because you need more space then the X4 isn't really the answer. It's spacious enough but a mechanically identical X3 is more so and less expensive to boot.

 

Better yet, speccing up an X4 can be hugely expensive, so much so that you might actually get better value from an X5 - and the X5 is at least twice the car that the X4 is. Weigh up your options carefully.