They should have the edge in the inside game, however, we should be able to beat them in the backcourt. Melo, is not a solid defender, Amare, can at times but often lacks focus, but Chandler, is a good defender.
They are a good PG away from being really tough. I also think they are a matchup nightmare for MIA now. I think we match up better against them given Rondo and Ray Allen. PP and KG will find a way to contribute each night, one can't say that about LeBron and Bosh.
So, yes, I think for now we are better than the Knicks. I also think we have a better bench and coach by a fair bit.