I too was looking at Challenger,Massey and Agco. As I see it the Massey 1533 replaces the 1433. Challenger MT 265 was the same as 1433 and Agco ST 35. The MT 265 B might be the new 1533 and I see Agco has new ST 34 A. Are you all confused yet? me too. I think I'm going with my first real love...