Think about what size bars you run and the type of wood you cut. The 250 is good for limbing and a 16". The 562 could run a 20", maybe a 24" if you're cutting pine but I wouldn't want to bury it in hard wood. I'm not sure it could oil a 28" very well. The 576 could run a 24" or 28", or a 32" (again if you're in soft woods.) The 660 gets you up into the 32"/36" territory, but the weight is a major penalty. While you could use it with a 24" bar, I'd rather pack the 562xp and cut from both sides.
If you mostly are cutting down around 20" and then get into big stuff (stumping, milling, old-growth etc), you could sell the 576. If you keep seeing wood in the 20"-30" diameter, I'd keep the 576xp.