[johnsimion]

Answered by someone who traded in a Boxster for a Cayman:
1) Wife doesn't like convertibles. That is reason enough.
2) We live in a climate where it is either too cold or too hot to use a convertible more than about 2 months a year.
3) All the cr@p they put on the roads here for snow ended up on my Boxster's convertible top during the time I owned it, making it age prematurely. There is no good way to wash your car -- especially to do a deep-clean of the convertible top -- when it is 40 degrees outside. Of course I could have parked the Boxster for 6 months a year, but what good is a car that you have to park for 6 months a year? The Cayman is available to drive almost all year and easier to wash.
4) Caymans don't squeak. My Boxster did. Not bad, probably better than most convertibles -- but it still squeaked. The Cayman is totally solid.
5) I just like the looks of my Cayman better, and I was fortunate to find the exact color I was looking for sitting on the dealer's lot.
6) My 986 Boxster had seats that were too short to protect my head from hitting the roll bar in case of an accident. The 987 doesn't have that problem, but I didn't want another convertible for the reasons stated above.
7) A Cayman may have a higher sticker price than a Boxster but will sell for less when the dealer has 20 Caymans in stock but only a couple of Boxsters.