I've been running my G660 for almost 3 years now. I replaced the clutch, muffler, and some screws before I finished the first tank and it has run great ever since. I run everything on 25:1 after seizing up my 064 on 50:1. Spark plugs are way cheaper than top end kits... For the first 5 gal of mix that I put through the G660, I was primarily running a 42" bar milling a 6' oak trunk into slabs that I could get loaded on my trailer to haul to the mill. That was early summer when the temps were over 95 degrees, and I normally worked about 10 hrs a day at it trying to get the tree cleaned up in the back yard. The sequence was run a tank of fuel, sit in the shade for 10 min and drink a bottle of water, refill the saw, touch up the chain, repeat. I lost 10 pounds that month. The saw did fine. I'd never a new 90cc power head that costs under $350 delivered to my door to have the same build quality as a new off the shelf OEM pro saw. If I ever need to purchase another saw, it will likely be blue.