I've used and installed several with pros and cons to each. The workman bb3 and T3 echo board are essentially the same board with different branded dipped capacitors on the board, all else seemed to look and function the same all the way to the dual variable control being identical. The rf limited boards aren't even available or produced anymore. Ranger has a nice eb2015 that is small, sounds nice and is even the same board you'll find in the new connex 33hpc1, mirage mx radios etc. My personal favorite because it's tiny, smd build, and sounds really clean is the Lt-2N echo board. I've had no experience with the delta but judging by the pictures they look kind of rinky dink imo. I have a eb2015 and current production lt-2n I'll snap some pictures of if you want.