One had a broken windshield...
That would be my S, VIN #61. I took delivery on the 24th in Vegas, drove in the afternoon to Hawthorne for the Supercharger event (stopping at the Barstow supercharger on the way), then parked in my garage overnight. The next day, the windshield had developed a stress fracture halfway up the right side. Probably a manufacturing flaw, exposed by the temperature extremes during the drive (90+ degree baking sun outside, AC inside, then cold overnight). Tesla replaced the windshield very quickly; good as new.
However, another problem soon developed, which is that after the system software update the computer's 3G went dead. The Tesla techs are having a hard time diagnosing it because evidently all their tools communicate with the car through 3G. (Go figure.) Waiting for word from headquarters on how they're going to fix it. So for the moment I have the car with no nav and no web browser, but otherwise working fine.
I've found a handful of other minor buglets and issues, not unexpected for such an early model... The frunk and front doors require too much force to close. Opening/closing the sunroof at highway speeds produces a loud whistle as it is about 10-15% open. Bluetooth sync is spotty; worked for a while then died, required a reboot to start working again. HomeLink took forever to recognize my garage clickers, even pressed against the front bumper. (Finally worked on about the 30th try.) In reverse, the backup camera feed automatically pops up, but covers over the HomeLink menu, which interferes with my ability to close the garage as I'm backing out of my driveway. The 110v adapter is limited to 12 amps, unlike the Roadster's which allowed 15... Charging is very painfully slow on 110v; about 3 miles of range per hour. I attempted to link up the Model S <-> Roadster HPC adapter to the Roadster's mobile connector in an attempt to get 15 amps, but this didn't work; it threw a "Car needs service" error. I hope this configuration will be supported in a software update, I could use the extra 3 amps!
Several other details already noted by others: The keyfob is cute, but nearly impossible to attach to a keychain. (It really should come with a tiny loop or lanyard attached. It also needs LED headlights!!) There's an odd two-tone chime when accelerating hard through 30-40mph, which is charming at first but annoying after a while. The speaker volume that "goes to 11" is cute, but really needs finer increments. The sun visors are awful. (too small, warped mirrors, no vanity lights.) Creep will be a welcome addition; at first I thought I'd prefer it without, but it's something like muscle tone; it makes the car feel "alive". Without creep, the car feels much heavier at rest.
All that said... I LOVE the car!!! Truly a thing of beauty.
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I sent all these notes to Tesla, btw. No substantive response back yet, except that I've been assured that it's going to the right people. They're very interested in early adopter feedback, and really do want to make the car as perfect as possible.