I purchased the Cayman to replace our '05 SLK350 and drive it primarily on weekends. I test drove most of the competition as well as the Cayman S and 911 Cabriolet. For me, the Cayman has the perfect blend of style, performance, efficiency and value. Sure, there are times when I think I could use the extra hp but those times have been seldom. Although some will tell you that they prefer the more "classic" line of the 911, I think the Cayman is in a style class by itself. Just hand the key to any valet if you need confirmation. If you want a livable, fun to drive two seater, I don't think there is any car on the market that can match the new Cayman.
This is the first Porsche that I have fit into, barring the sunroofless GT3. I have been in a sports car-less funk since I sold my '95 Miata R-package. The Cayman is the perfect replacement. It is a comfortable daily commuter with absolutely brilliant handling and perfect suspension tuning. The 2.7 liter six engine is an absolute gem, very flexible and aurally pleasing. It is also very practical with both trunks and cabin storage.
This is easily the best overall perfoming car that I have owned. It feels quicker than my BMW M3, except from 70 mph up. Its handling outshines all (for the money) except the Lotus Elise, but the build quality and sound from behind you more than make up for any performance difference. The ride quality allows for daily driving without punishment. Additionally, the manual transmission is wonderfully weighted and precise.
I previously had an SLK and a Z4 convertible. This 2 dr Cayman is so much more fun to drive. I feel like a million dollars whenever I get in it and have owned it for a year and I am not bored with it yet. I bought it used with low miles and would only trade it in if I was buying another Porsche.
I just got a new 2007 Cayman S model. I am very happy with it overall. It is great looking, well built, and has a nice interior. It's also very quick. It drives like a sports car, meaning a firm, but not harsh ride. I went with the 19" wheels. Some options should be standard, but that's Porsche. Its gas mileage stinks, but that's to be expected. This car has great German engineering all around, even in the smallest details.