I just bought my 2007 C70 this past September and the car is simply outstanding! The retractable hardtop-- the signature feature--is a marvel of engineering and truly makes this vehicle 100% versatile--a convertible when I want be sporty, a quiet riding coupe when the top is up, and a nice family car for the four of us on long or short outings. The car is sophisticated but subtle, not drawing unwanted attention and does not scream "mid-life crisis" but is instead a good balance of fun, fashion, performance, practicality, and pride. The engine has plenty of pickup, and the leather interior is luxurious and first-class. All in all, a great car and a real keeper for this enthusiastic owner!
Without a doubt, the retractable hardtop! This feature lives up to its advertising, making the C70 truly akin to owning two cars instead of one! I also like the power seats with shoulder controls (making it easier to move for back-seat passengers) and the Xenon headlights provide great visibility!
Three things I do not like: the windshield wiper control is too close to the ignition (and I bump it whenever I reach for the key); no convenient place for loose items; and having to hold the button down the entire time to put up or take down the top (though I can see the safety reasoning for that).