Theoretically, if you're better than average, it should be to your benefit to queue early since there should be more people worse than you as opposed to better. But then again, the people that are really good are more motivated to play early and often, since they'll be trying to get 2050 for weapons asap.

I started queuing day 1 of Season 3, and on my battlegroup, I don't think anyone was over 1700 after the first day. It could be that the hardcore people just kept playing through the night and their armory didn't update though. I think our 5v5 (which was rated 1950 at the end of season 2) went something like 10-10 on the first day and we ended up like 1510. Luck of the draw.

I'll probably wait until Thursday to queue, but that's more due to the fact that I'll have so much new gear to gem and enchant that I'll probably be busy all Tuesday with that, and all my teammates raid on Wednesdays.