I think there are advantages either way. If you register later, you can avoid some of the loose play that goes on early, especially in large fields. There always seems to be one knucklehead at every table who is convinced he can win the tournament in the first 20 minutes and goes all-in every 3 hands. But you are also at a disadvantage in that your starting stack is now going to be significantly lower than the chip average. Registering early, however, gives you the opportunity to clean up on some of the loose play, so it works both ways. If it is a turbo tourney, you really need to get in early. A slower paced tourney with a big starting stack is okay to join later.