When you step into the teleporter, there will actually be two future selves created: one will stay in the teleporter chamber, the other will go to the destination. So to decide if you should do it your not, you need to weigh the benefits to 3 people: (1) your future self if you don't go into the teleporter; (2) your future self who arrives at the destination; (3) your future self who stays back anyway, so who is very similar to (1). If (2) is much happier than (1) and (3) is not significantly less happy than (1), you should rationally do it. If (3) would be significantly less happy, there is also the option of considering having them (painlessly) killed in the process.
Either way, the person making the decision will not get to experience either (1), (2), or (3)'s experiences.