Depends on the racing you will be doing and what your budget is. Ideally you would be on something new, rolls very free, turns easily without scrubbing corner speed, and works well on whatever tires you will be running. Brand makes little difference but knowing the drivers weight might get you on the frame stiffness you need. To win in box stock you need a kart that requires less brake and more corner speed than everyone else. Any of the kart manufacturers can get you there.
Don't be torn away from the idea of getting something "older". There's lot's of arguments on here about age but honestly the consensus is that a few years old won't hurt you any (especially if this is your first year racing).
Search for all the posts on here about it and you'll find tons of information.