I bought the Holtz G660, G366, and G111. I was not impressed with their cylinders, so brand new, I pulled them off the G366 and G660 and ported the intake and exhaust mildly, but the main reason was that they didn't have a good chamfer at the corners of the intake and exhaust ports and the piston. It appears that they just bore and hone the cylinder with no chamfering, which is not good for longevity. I would recommend that if you buy one of their saws, to pull the cylinder and dremel a little chamfer on the intake and exhaust ports first thing before using the saw. I muffler modded all three saws, but due to the complexity of the G111 I did not mess with the cylinder. I did some cutting with all of them, but unfortunately the G660 and G111 got stolen, so I can't comment on their longevity. I recall that the coil on both the G660 and G366 went bad on me and I replaced them with aftermarket coils from another company. In shipping the G111 chain brake anti-kickback handle got broken, the company was quick to send me a new one. I had their 24" bar, it was okay, not sure I would use it professionally though. Their chains seem to stretch a little and are okay for homeowner use, but I'd recommend a better chain. The G660 has some good power, but I don't think it was as good as my Stihl 066 with a Metor piston and cylinder on it, sadly this saw was stolen too. I previously had a Stihl 036 saw and the G366 seems comparable in performance. Both the G660 and G366 leaked bar oil. Recently I've had some problems with the G366 carb, I'm not sure what the issue is, I suspect some dirt or wood got into it somehow, but I will have to try and clean it out. I was happy with the way all of the saw cut wood, the G111 is nice to have for the little stuff after the muffler mod, it was a little weak before opening up the muffler port, but after the muffler mod, it came to life.