spmd11,
I went from an '00 Yukon to an '05 X5. Well...actually I still have the Yukon, but my daughter will be driving it soon. Anyway, I can give you my thoughts:
1. The X5 is long on sport, short on utility. You'll miss being able to throw anything and everything in the back. But you probably already figured that much out.
2. X5 is a "drivers car", much more throttle responsive than a big clunky SUV. It feels like driving a big, safe tank. A tank that can go really fast.
3. My X5 had some squeaks and rattles, I've fixed them now but I have to admit that it really surprised me that an expensive car is plagued with such annoyances. My old trusty Yukon had nary a squeak or rattle, ever.
4. Is it a good value? Well, it depends on your definition of value. They're probably as "cheap" as they'll ever be since the market isn't very hot right now. And the finance rates with BMW are very good. The Acura MDX in the '04 or '05 model year would be cheaper, provide more utility, but it wouldn't have the same appeal as the BMW. That's a decision only you can make.
For me, I was kinda tired of driving a big full size Yukon around, and wanted a change. BMW had always interested me, so I figured what the heck. I paid less for my '05 CPO X5 than I did for my new Yukon back in 2000. At least, that's how I rationalized my purchase
Will I keep it forever like my Yukon? Maybe...maybe not. I like it, but more than likely next time I'll probably go with something a little bigger. Maybe slightly bigger like an MDX, or even back to a full size like a Tahoe.
I'll enjoy it for the next couple of years and see what happens. If you do decide to buy the '04, good luck with it. As long as it's a CPO unit, that takes a lot of the repair worries away.