Similar points, ft% and threes. Artest will get more assists, steals, blocks, and better fg%, Jamison will get more boards.
I think your team can use the extra stats that Artest brings over the 4 boards Jamison will give. BUT how many games will Artest miss, and how are his numbers are affected by his new teammates? Also, how much will Jamison carry the team while Arenas and Haywood are out?