This car is not the best in any category, there are better looking, faster, cheaper, whatever the category. But as a package, this car is the one to take out on a winding road on a Saturday afternoon. Or you can just drop the top and actually enjoy your drive to work, as I do. It has all the power you need to be pushing well to the right side of 100 by the end of the average on ramp. It sticks to corners like glue. And yet is behaved enough to not look like you are finally living out your high school fantasy - even if that is exactly really what you're doing.
Unless you have deep (very deep) pockets, or are comfortable doing routine maintenance on a high-tech vehicle, the 645ci probably isn't your best choice unless you're able to purchase an extended warranty. I drove a 1984 633csi for about 20 years -- thoroughly loved the car. When work required more travel, I upgraded to the 2004 645ci. I was able to pick one up a 2-owner with 85,000 miles for right around $13K. Financed through the credit union and added a $3,200 3-yr/36K bumper to bumper warranty; total price $16.5K or so. (warranty paid for itself the first trip to the shop when the transmission started leaking -- $5,300 expense; I had to pay a $100 deductible). The Bimmer is a FANTASTIC touring car on the road and fun to drive around town... Has plenty of power and a beautiful and unmistakable design.
This is a magnificent car, providing more niche-fillers than any other car on the market: a true sports car, with excellent speed and handling, top luxury, eye-catching look, available with a stick, and a back seat and trunk that are actually useful. However, the alloy wheels are so soft I'm on my my third set, and despite their advertising, BMW will do anything to avoid having the warranty cover anything more than the usual minor issues. The software on the care is unreliable too and the car is a gas hog. Even so, I love it, but it's hard to accept being treated poorly by BMW given the nature of their advertising and the cost of this car.
What I think is best about this car is how well it operates in the two roles of luxury cruiser and sports car convertible. Overall it is exceptionally self assured and holds the road with tenancity. The low grumble from the v-8 sounds great. As a luxury car it compares to anything out there. But put the top down, select the sport setting on the transmission and you have a car that will give you all the excitment you want and remind you of what fun driving is. Additionally the aerodynamics are phenominal. At any speed up to 80 mph, with the top down and windows up the car is quiet and there is virtually no wind buffeting in the front seats.
Love the car, drives like a dream. Brakes are wonderful. Car attrackes a big crowd. Unfortunitly, severe creaking with body twist and active steering gets floaty over 105mph. Back seat is just for groceries. Car has been in the shop for total of 15 days and 4 trips in first 2 months, all computer related. No radio, no phone service, navagation meltdown, iDrive meltdown. This car was just not ready to be sold to the market, they needed another year to work out the bugs.