I was just getting ready to msg you, lol. I run both, been mostly using the 500i, dual port muffler. I like the 500, the weight is awesome. Other than the weight I like a ported 572 WAY better though. The 500 will cut a little faster but the chain will actually stall easier than the 572. I have 2 500’s and their both the same. I know according to others and specs it shouldn’t be that way but that is my experience. With 32” bar and moderately aggressive chain the 572 will slow down but it keeps pulling, the 500 the chain just stops if you put too much pressure on it, very frustrating. The 572 also has a larger clutch cover and chip flap so chips are directed down instead of at the operator. It’s also a little smoother.