Weight and balance are two different things. Balance doesn't matter too much when bucking at a landing, but it sure does when falling and limbing in the woods.
There is only one reason to buy an echo. Price. And in Canada Echo has priced themselves out of their market. Well two reasons actually; if you don't want autotune carburetion.
Echo wants about 1800 dollars CAD for the 7310. Are they out of their minds? Betcha they are not selling very many here. Like almost none.
I'm not anti echo or pro stihl/husky whatsoever. I'm just a realist when it comes to equipment.
I have three 60cc saws: an OE MS362 (not the turd; the early mtronic one was a little wheezy due to automatic lean settings constantly), a cs590, an an OE 262xp (1990 model) and I have ran others more recent, but not the most recent. The cs590 (I know we are talking cs620 here, but there's not a lot of difference, really) is not in the same class and is not meant to be. OP, if cost is not a concern and you want a rip-snortin' saw that handles beautifully, has superlative antivibe, and has a top end rush of power get the stihl or husky. Just go look at them and roll them around in your hands. Look at how they are put together, with excellent fasteners and quick release "hoods" and such. There is simply no comparison.
For some reason Echo does not port for highest performance, nor even try to compete at the highest level in any way.
The last time I saw an Echo on a job (sometimes with as many as 50 or 60 saw-hands) was...Never.