If it is a buy in that matters, I prefer to register early, gear up mentally, for the long haul. If it's a freebie, might as well register late, freebies are so large, number and time commitment, may as well be desperate from the beginning, shoving a lot to stay on upper rungs of the leaderboard.
I prefer to sign up early than late. I would rather build up my stack smartly and slowly compared to signing up and have to go all in early and often because I have no chips to start with and need to gamble. I also believe my building up the stack earlier and having it once the late registration players join up give me a better chance to go deep and possibly win the tournament.
I agree that in the very early stages you will have more opportunities to stack off some weak opponents , on the other hand something that happens often to me is after a decent amount of hands and after understand how my opponents play the poker room switch me table which really sucks.
I don't like ACR/BCP 3 hours late registration but I feel that 2 hours which most of the rooms have for a regular speed tournament is fine. The last minute players have only one option - open jam -.
Personally I like registering when the antes come to play because the crazy players have been eliminated and the real poker begins.