Besides storage space, in my opinion there are no negatives to getting a hardtop. You have a few options for storage: a hoist, a rack, or a wall mount. The top isn't particularly heavy (55lbs) but they are big and awkward so you will need two people to take it on/off without a hoist.
A few things to note:
-Once the hard top is on for the winter, leave it on. Putting your soft top up/down below 70° F will risk cracking the plastic window, unless you have upgraded to a glass window
-The hardtop will take a while to settle/mold to your 986, and will need to be adjusted (3 screws on each side above the spinlocks) for the first few weeks to get the best, least squeaky fit. I have written how to do this before, a search should turn it up.
-Cut a piece for felt/fleece to place over the plastic window when you fold the top for the last time, or use PN: 986 563 855 01
-If you are driving below 40° make sure you have winter tires, or at least all seasons, summer times are very risky below 40° F
-If you ski get a RTS.
