I'll be different and say I like my MS650. It's a true 80cc class saw at 84cc. But you may as well get a 660 for the same weight with more power. Although I have read that the 650's hold up better than the 660s? Something about there not as hard on the bearings and the ground guys out west on the landings used them instead of 660s as they tended to last longer and we're a tad cheaper. I but mine as a SIB for $20 so it's not like I had a choice just bought the deal.
There was only a $100 difference in between the 650 and 660 new. I had to dust off the 650s much more frequently than the 660s.
I like my old 133 Dolmar wearing the 36" Here's a little noise and a dull chain from a few months ago