[wtwo3]

In some cases just the availability of certain options.

I recently ran into this situation when we were shopping for a new SUV. We didn't really need the X5, as the X3 would have been more than adequate for our family of 3.

But I happened to sit in the X3 and X5 back to back, and holy crap the difference was night and day. The materials quality, seat comfort, and overall feel was significantly better in the X5. Everything felt way more premium, and that pretty much sealed the deal for us to get the X5.

Beyond just materials quality, the availability of options was a pretty big difference:

Things the X5 offered that the X3 didn't:
Air suspension - made the ride silky smooth
Massaging seats - great for long trips
High quality marino leather - much softer and comfortable (and way better looking) than the vernasca in the X3
Glass controls - really gave the cabin an upscale look
Soft Close Doors

In regards to the technology side - you're correct, there wasn't a huge difference in the tech offered between the X3 and X5. But it was the intangibles like the overall quality of materials and just how luxurious it felt sitting in the cabin that sold us.