That may or may not be true in regards durability/trouble free. Most of the guys on thisnsite will never know because they will never accumulate enough hours to wear a saw out.I wouldn’t expect a 620 to perform like a Stihl 400. It’s not meant to. But I’d bet my children it would be more durable and trouble free. The price gap isn’t representative of the performance difference. If you you want a faster, stronger saw, the 400 is the one. If you want value and a saw that mostly cuts at the same capacity, it’s the 620.
With Echo your buying a 30 year old saw that's 1hp down from a 400C and as such you pay less.