Our clubs experience is with both MEC & Promatic sporting clays traps. Some of my comments may not be relevant in a trap field installation.
Visually, MEC has far better metal work, metal finish & painting. The MEC has a counter balance on the throwing arm & has less shake when fired. The Promatic does not. The MEC does not require tools for elevation & side to side tilt adjustments, the Promatic does. This is not very important in a trap field installation.
Parts service is excellent for both. Parts we’ve ordered on a Monday morning have been delivered by Thursday noon. Both have excellent over-the-phone tech service. Their people know what they are talking about.
Feel free to PM me if you have questions.
Bob.