You install the shell via preinstalled adhesive strips on the interior surfaces. The bottom of the laptop slides in with two small straps covering the front left and right edges, while the top panel has a very slight overhang just in the center to hold onto the lid and also provide a finger grip for opening the laptop. The adhesive pulls away without much trouble, but I'm sure repeated reinstallations would kill the adhesive strips pretty quickly.
When installed, the shell leaves the ports on the left and right edges of the MacBook exposed, so you won't have any trouble getting to them. The keyboard and touch pad are likewise unencumbered, although having the two tiny straps across the left and right front edges does break the symmetry of the leather and aluminum.
It's a valid concern to worry about excess heat from covering most of the outer surface of your all-metal laptop with thick leather. In anecdotal use, the MacBook did not seem to run hotter, or use its fans more frequently, but note that the vents on this particular MacBook blow up from the bottom half of the hinge assembly, and the leather blocks very little, if any, of that air.
Besides being more expensive than any other laptop shell or cover we've seen, the Leather Suit has one additional disadvantage. While solidly built, it's also heavy, weighing 0.94 pound. That means adding it to this 13-inch Retina MacBook took us all the way up to 4.6 pounds -- which is a big increase in travel weight.
The Vaja Leather Suit is definitely cool-looking and built for long-term use, but also expensive and heavy -- the latter point can defeat the purpose of having a MacBook Retina or Air model in the first place. But if you don't mind paying a premium, it'll help your MacBook stand out from the crowd, while still feeling just as high-end.