So the old rule of thumb was bet on Ireland. Bet against Italy. I don't think that second part is true anymore. I think they could cause issues for current form France.
The rest of the nations... Roll the dice, any given day England could beat everyone in the tournament or they could bust against everyone. It seems really really close from the quality of rugby at the weekend. Ireland do look elite though. I don't think anyone would be able to match them this year.
I know that's not particularly helpful. But this tournament seems wide open outside of Ireland.