An exosuit is like a cross between Iron Man and a mech. It is a small humanoid mech that fully encases the pilot and directly responds to their motions. In Starbound piloting one would be just like walking around normally except for the height increase, and some other things depending on the suit. Exosuits, first of all, are not gear. They are whole vehicles that you can enter and exit, and that you can not store in your inventory like armor. They would be repaired, built, and researched like mechs, though the research would also lead from normal armor. So...why would you want an exosuit? First of all they provide an incredible armor boost without dampening your mobility much like normal mechs. Some exosuits would let you run faster, most jump higher, and some would come equipped with climbing abilities or jetpacks. They would have built-in weapons of various kinds along with special utilities, anything from invisibility to flashlights. Some exosuits would have that building ray gun too! Ok, but that sounds way OP. So why would you not want an exosuit? Firstly, because while it does have all those abilities (not all at once of course, but depending on the model) they are still vehicles and probably won't fit through your front door. Unless you blew open a new one with it. In battle they would make you a bigger target and wouldn't stand up to a real combat mech, or just about any mechs' foot. They would also be very expensive and without a lot of the useful parts of normal vehicles, like storage or advanced mining or real firepower. Lastly, you would not have any of your personal gear or its effects (such as energy shielding, if they add that) around your suit, so you have only it to work with and maybe your blocks.