Any thoughts on the X7 M50 or M60?

[Dodgey_Rog]

I'm having to change my Land Rover LR4 as it's starting to get too problematic and has developed an oil leak!

I need to get something of similar size, comfort and needs to have some grunt. I've had an X7 before as a BMW loaner when my M4 packed up on the collection day. That was the 4.0i X-Drive, and was a decent car, good spec, comfortable and had some get up and go for what I needed it for.

This is my car for the US, so everyday use in New York with regular trips upstate and out east, so motorway driving. The M50's and M60's look appealing but wondering if anyone's got any insight into the running of these. I'm past the looks as I gather that's controversial, but I'm going for space, comfort and decent spec as the prices over here are working out pretty good.

For comparison, the Audi RS Q8 is a potential contender, but I'm struggling to justify the extra expense as the prices are a little more over here when you're comparing apples to apples.

Hoping to hear some real-world experiences and if there are major factors to consider with these road-boats.