Drove both extensively - GTS (tip) vs X5 4.8i
IMO- Looks - even
- Interior - GTS (even comparing X5's full leather).
- Quickness - Seat of pants favors the GTS
- Handling - GTS (as good as the E70 handles)
- Electronics - X5 (RTT, better iPod integration)
- Exterior - even
- Must have - GTS (a lot less of them on the road - even with the base/S variations)
- Value - X5 by a mile. Modestly equipped GTS = $90K

- Also: Residual value (I'm a lease guy) - X5 by a mile
If the GTS was the same price and if the residuals were close (they are > 10% below similar X5 lease terms), I would have ordered one.
For > $90K however, you're in a different league. I decided (easily) that I'd prefer to own either an ML63 or the soon to arrive X5 'M'.
///M wins