I think that the biggest advantage is no more petty bullshit. Who cares who is going out with who or what you are doing that friday night? When you wake up everyday, and you have no idea if it will be your last day, or just another day closer to your last day, you learn to appreciate every breath you take. You care about things that you never cared about before. The sky, a breeze, the grass on the ground all become important things.
However, a disadvantage is knowing that ultimately, no matter what, you will eventually be alone. At times, that can be good. But when it comes down to it, you need people. And if you manage to make it on your own, that's just it. You are alone.