I have an Emerald with my Twin Spark and Spica throttles. I like the interface and it was not too difficult to wire. When you tell them what engine you are using, not only do they send you a base map, but they send you a wiring table. They will also answer your troubleshooting emails. I am very satisfied with Emerald and their support.
For some reason, it seems to be a widely held choice when using throttle bodies. The maps come standard with the rpm vs throttle position. There is a MAP compensation table, but I haven't been able to figure that out yet. I'm just using rpm vs tps. My MAP signal is not very stable even though I've done everything I've learned about damping the vacuum pulses.
If not using throttle bodies, or if your MAP signal is good, you can change the vertical axis to MAP. It is not obvious, it's kind of hidden in the settings somewhere.
I can relay my gotchas when you are ready to start up. Good luck with build and post lots of pictures.
iachella [at] gmail [dot] com