I ended up getting a 4iiii Precision Power Meter, and it has been working great. Love that I don't need a cadence sensor anymore. I ended up buying a Wahoo speed sensor, too, so I could get rid of my Garmin GSC-10.
I had a time trial this past Tuesday. I rode this course last August for the first time (first time trial in 25 years, too), and turned in a time of 28 minutes flat.
This time, I had my Garmin Edge 1000 telling me how far ahead or behind I was based on Strava Segments. Ironically, I thought I was behind the entire time, because it turns out that I had ridden 2 roads of the course with some friends in a pace line, and those were my best times, not the times from my last time trial.
My result was 27:16. I definitely needed to concentrate more on the riding, because I caught my heart rate falling to 171 a few times, and I wanted to keep it between 175 and 180. My average power was 204W. I definitely want to push that up with training.
I had a GoPro on my bike for the ride, and I overlaid my Garmin's sensors over the video using Garmin VIRB Edit. I think it came out really well:
https://youtu.be/P98ML7DZv3k
Here's the Strava ride:
https://www.strava.com/activities/990788174