I have the following;

Simjet 700 Gaspar ECU
simjet 2300 D-2 ECU
2 Simjet 3000 Gaspar ECU

All of these engines are good running engines with fast spool up and decent fuel efficiency.

I have had a 14 lb 1200 that also ran great and another one (18 lb version) that gave me nothing but trouble. I believe the majority of the issues were with the ECU as it was one of the first aluminum case ECU's with early software.

You havn't mentioned which size you were looking at.