It has been a while but I thought I would add my .02
I have a 575XP and I have been very happy with the saw. I have had mine for almost two years, I got my 575 from Bailey's. I use a 20 inch bar for just about everything however, I do have a 32 inch bar that I have used several times. I was suprised how well the saw cuts with the 32 inch bar. I was cutting through some huge maples. The 32 inch bar goes through white pine like a hot knife through butter. The 32 inch bar really throws off the balance of the saw.
It is important to note that on the 32 inch bar I do use skip tooth square ground chains. One the 20 inch bars I have been running round ground bumper link safety chains, that i got really cheap from Bailey's. I would not recomend the safety chains becuase wheneven I go from the 32 inch bar to the 20 I feel like the 20 inch is cutting a lot slower.