I have a 575. I have only run about 5 tanks through it so far. Its the biggest saw I have ever run so I don't really have anything to compare it too. It cuts alot better than my J-Red 2065. I have had trouble restarting it once after shutting it down. I have bogged the 24'' bar in some monster oak before, so I have been weery to run the 32'' bar until its broken in.
The guys in the chainsaw forum hate these saws and they will all tell you to get a 272 or the J-Red 2171. I think they may be overreacting a little. I guess its heavier and not as well balanced as the others. If its a firewood saw I really don't see their point. Heck, I cut tons of wood with my Olympic 264, and it doesn't get any heavier than that. Overall I think its a good saw. I would like to try a Dolmar 7900 though, and would love to get one but the dealers near me seem to be nonexsistant even though they are listed on Dolmars web site.
Hope you got a good deal and let us know how you like it.