flip a coin
My wife has a 03 500SL Sport, I got my XLR on 5/15/04. They're both great cars, but I prefer mine. Friendlier controls and readability. I love the head-up display (not available on 500SL).
Both solid great rides and handling. Touch screen much easier to use than the buttons on the 500SL.
500SL has more trunk space with top down, I can't get a golf bag in XLR unless top is up.
Adaptive Cruise control in XLR is better.
500SL has spare tire, no run flat. Wife hit a pot hole 3 1/2 wks ago, bent wheel and ruined tire. No wheels available from Mercedes. After waiting 3 wks & being told wheel was back-ordered until at least end of Sept., I complained loud enough that they took the wheel off a new car & put it on ours.
Cost: $1,200.
We paid $106,000 for the Sport 500SL in Jan 03, it's now selling for 82-87,000. Mercedes doesn't include the cost of all servicing in the sale price like the XLR does. Normal maintenance is fairly expensive on M/B.
I suspect I will have better traction in winter-time because of the 50/50 weight distribution.
Finally, I like the XLR styling better. rex32