My bar was buried in that trunk - you didn't mention anything about that.
I already told you I own an Echo chainsaw, and I have used them professionally in the past. I LIKE them(modded) - even if some of them are Shindaiwas. I have no bias. Zero. It either works, or it doesn't. I do not care at all about the brand. I have an MS361 because it works. It replaced my 372XP. I own or have owned all brands, including Macs and Homelites, etc.
However - the extra length always matters, and you know that. If you have to oil more bar, pull more chain weight, and have more resistance, you WILL be using more power. You can't ignore physics. If you compare two saws - keep it simple. Otherwise, there's no real use getting so excited. Lets try to keep some perspective - Echo does not have some sort of magic answer to 60cc saws. You will be hard-pressed to convince those of us with real chainsaw experience it can somehow compete with any modern well-ported chainsaw in the same class with the same set up.
Hell, I think my lil ported CS520 could give that 600P a very hard time:
