If you're fortunate enough that your vehicle gives the option of either a leg kit or spine to attach your platform to the roof you may be wondering which is the better choice for you. Both have their advantages depending on what you are carrying, and how permanently you want the carrier to be on your roof. As well as your budget and preference.
Leg mounts are the most common and generally cheapest option to mount your platform or tray to your roof. In a lot of cases, they are the only options you can get to suit your vehicle. Even if you also have the option of a 'spine' mount the legs do have their own advantages. Leg mount fitments are the cheaper options, they are also easier if you want to remove the platform from the roof for cleaning or just because.
Spine systems that go by different names from each brand are an option not yet available to all vehicles. If you are one of the lucky ones that can fit one to your 4WD you may find some advantages over the leg mounts. While looks are subjective, I mean c'mon they look better, they will also offer a static load rating, which is important when using a rooftop tent on the platform.