I only read a few posts in this thread. The predictable arguments between the usual antagonists didn't take too long to show up. :msp_sad:
But to answer the OP's actual question, Echos are not catching on and they aren't going to. And that's not a knock on Echo product which has always been decent stuff. Two weeks ago I got to run an old 650 something twin cylinder, and it was a really cool saw. The new saws, like the 600 that you guys are talking about is also a nice item. And most Echo saws in between those two have been fine.
The reality in the saw world, and it's not gonna change, is that Husky and Stihl are the only two brands on the lead lap. They literally own the market. They are usually perceived as competing with each other for top dog status, which in many ways is true. But if you look back over the last 20 years, they have captured market share not so much from each other, but from everyone else who are now left clinging to single digit market share.
One of the things guys on forums such as this can get fooled by is the "this is the saw" false hope. What I mean by that is the thought that a new model from a second tier company is going to be the one that turns the market on it's head and actually moves the needle. The Echo 600 is a fine saw, but there have been other great saws that also held out this false promise. Dolmar 120SI, Olympyk 970. The Dolmar 7900 would be a more recent example. All great saws in and of themselves, but only a small piece of the puzzle needed to gain traction in the saw market.
You take a broad angle look at the size and strength of what Husky and Stihl have going for them and the idea that any other company is going to have any significant impact on them is simply not realistic.