I also have the Pro Pilot in my RV-10, and like it a lot.
One small correction to John's post: both the Trio and the TruTrak (if purchased with the GPSS/GPS options) will fly a GPS LPV approach if connected to a WAAS box like a G-430w or G-420w. But both need to be connected to an EFIS like the GRT Horizon to follow an ILS.
I have also instructed in a -10 with a TruTrak. It also works fine.
Pluses for the Trio:
1. I think it is easier to understand what mode the Trio is in, and what button to push to do what, because it has a larger display, with more buttons, lights, etc to enunciate exactly what it's doing. Down side is it occupies more panel space.
2. I really like the Trio's trim option. Not only does it auto-trim when the autopilot is in control, I use it when hand-flying the airplane with the autopilot on but disengaged. The trim speed varies inversely with airspeed, so at cruise it is easy to make fine adjustments. I don't think the TT can be used in a manual mode like this.