[speeddeacon]

We have a '16 750ix and I have no experience with the new 5, but I imagine it depends on what you want from the car. Similarities will be more common than differences as they are very closely related.

The 5 will be a bit sportier. The 7 will have a bit more luxury car feel due to the suspension and the girth. The 5 will feel like a mid size in the back seat. The 7 is simply cavernous back there for your passengers.

Straight line in the 750ix is superb for such a large car. I imagine the perceived acceleration will not be altogether different in the 5, even though its lighter weight allows it to sprint quicker on the clock.

The massaging seats in the 7 are amazing. If you can't get comfortable in them it is because you want more padding, not due to shape or adjustability. The ride is sublime and all day cruising imparts no fatigue or soreness. However you state the Pilot will be your high mileage trip vehicle anyway. I'm not sure if those same seats are available in the new 5 or not. If so, that could be a neutral factor.

In my opinion the 7 handles like a luxury car, not a sport sedan. There is just too much body roll when cornering, even in Sport mode of the active suspension for my taste. That is not everyone's opinion and for some is a positive, just not to me. It's a trade off for the luxury and comfort it seems. My previous 5 series' have provided a much better cornering experience. YMMV.

So to me it would boil down to size, sportiness and price. If you don't need the room and don't want the luxury feel over a bit sportier one, it would be a no brainer for me, save the money and get the 5. If the opposite is true, you have to decide if it's worth the extra $$.