You couldn't go wrong with either of those choices from what I've seen. I, personally, would go with Tesla just based on the charging network and their tech. I've heard the X is a bit like driving a VERY fast bus. It's much bigger than it appears to be at first glance. I'd recommend test driving both if you can.
My Model 3 is extremely comfortable but the interior design quality probably isn't up BMW standards, to be honest. I would equate it to Toyota quality, which isn't bad but isn't exactly luxurious. Tesla's cabins tend to be more minimalistic, which I like, because that means less things to break. The best way I can describe the Tesla driving experience is Zenlike until you step on the accelerator and then it transforms itself into something close to a supercar. It feels like stepping a decade into the past when I drive a traditional car now.