If you want *good* AYCE sushi, there really isn't anywhere else to go (for under $25). Echo doesn't get everything right, so part of the fun is knowing what they do get fresh - and that is the salmon frickin' sashimi. Honestly, order a ton of that and whatever maki rolls you please (firehouse and jade dragon are 2 of my faves, but they are all ) and you won't be disappointed. I've had the salmon every single time I've gone and my visits have numbered close to a dozen times a year. Echo hasn't missed a beat in that dept.
As to what to avoid...I wouldn't waste time or stomach space with the tuna. But seriously, if you want good tuna, you shouldn't be going to an AYCE joint