I had the chance to cut with one of the new Echo CS-620 saws last week. We had the CS-590, CS-600 and the 620 all in a row and cut from the same log for comparison. The 590 is no slouch, and for the money there isn't another saw built as well, but there was a noticable difference going to the 600 then the 620. I think the 620 was 2-3 seconds faster through a 10" diamater hemlock. Also the 620 will be available with a wrap handle and double spikes from the factory. I cant wait to get my demo saw so I can break it in and really see how it wakes up.. Oh, in a bizarre occurance, the 620 was set way rich from the factory, almost 3/8 of a turn to lean it out so it wasn't gurgling.