Heard from a sales guy they are awesome.
So being in the Baton Rouge area where Marucci is from, it appears that the Echo is doing pretty decent. There are several regional Marucci teams that have to use Marucci products only. The higher end teams can rake the ball with it. Lots of pop and a good sweet spot. I know a 12u girl that was picking up for one of these teams and smoked one over the fence and, while he is an excellent batter, is not generally known as a power hitter. I have heard of at least one that broke in the first month of use but for the most part, it is doing well around here. I'm not sure of the science behind it but supposedly the sweet spot was as big, if not larger, than the ghost advanced. Also, exit velocities are hot on it.