gene2586 -- I also have a MECOA .46 Tomcat, in addition to 5 TT .46 Pros. There is absolutely no comparison. All five TT's routinely tach @ ~13,200 rpm with an APC 11-6 prop on 10% nitro, while the MECOA has never exceeded 12,400 with the same setup, despite very carefull break-in (which was long & painfull with the MECOA). The TT's start more easily (single flip every time), idle more slowly & reliably, & transition much more cleanly.

The MECOA is not much cheaper than the TT Pro, but while it works acceptably well (I still have it), it is not nearly the engine that the TT Pro is.