The info I have is that the 620 is an improvement over earlier Echo designs - but still is way too heavy for 60cc, and low on power as well.
why “way too heavy” seems to be pretty average for most 60cc saws as far as weight goes. And “low on power”? Again just about the same as the 562 and 362..... But from what I read of your posts regarding echo saws you probably wouldn’t like them if they were lightweight either