For a high dollar jet it seems the "popular" choice is between the Cortex and the iGyro for most guys. I've flown the Eagletree in various versions and they are cool but I don't like the way they "feel" knowing what I do know today. The jets I used the Eagletrees on were medium to higher wing loading swept wing traditional jets (one rudder, two ail channels, etc). They felt solid and nice in landing configuration but while in flight doing aerobatics I had moments asking myself if I was flying the plane or if it was being flown by a robot. I was almost fighting the controls at times and something did not seem natural. I spent a lot of time on the computer fine tuning the setup and researching other people's setups but never liked the feel I was getting. However in a small foamie they are fine. I last flew the ET's toward the end of 2013 in anything "decent".
On the other hand I have nothing but acolades for the iGyro 3e. I can't believe what a better flying experience the iGyro is - it feels like I'm the only one flying (no fighting with some other "layer" of control going on behind the curtain) but the bad habits in the airframe like dutch roll, axis coupling, pitch oscillations and momentum overshoots are gone. May I add, I have grown to love the ability of the iGyro to offer an "attitude hold" mode that is not only useful but absolutely appropriate with experience and proper setup. I've never liked that sort of mode before on the ET's but in the iGyro - it's a sleeper of a mode with tons of potential if one is able to put some time in playing with it in a low value model first. In general, just talking rate mode though (the normal mode most guys play with)... what's cool is you have the ability to put more mental resources toward fine tuning flight path control and energy management with good gyro systems. In other words you have more capacity to fly better because you are just flying, not fighting. The plane is much more pleasing to watch. It looks real. It's not bobbing around in it's own airframe wake or random thermal activity as you bore holes in the sky. It flies "bigger".
I am certain the Cortex is the same. I have two iGyros and DO plan to also buy a Cortex later this year. For right now I have ditched the idea that I'll only have one of these gyro boxes (my original thought). For example, planes I often fly the same day, it would be nice to have a box installed in each. I'd prefer not to pull these at the field swapping things around in some planes with tight space when I should be flying and jiving with friends... but... I also won't have one in every plane bc they are still a ton of cash. I'll have a quick mount set up in my planes for easy swaps in the shop so maybe I'll have three of these (2 iGyro and 1 Cortex for example) by the end of the season. So I'm not bothered about any potential brand war or fan boy club making me feel like I can't have both. I will have both. This may be a case of the Cortex having it's best performance in certain types of planes and the iGyro having the performance advantage in others.
All I know is I'm sorta sold on these little black boxes. Or blue boxes. Or whatever.