trainingpeaks/WKO+ and golden cheetah are the two biggest favorites.
golden cheetah is free and may provide all you want/need, at the moment the official version uses slightly different metrics than WKO+ (BikeScore instead of TSS, etc) but they are very nearly indentical.
trainingpeaks as the advantage of being easy to share data with coaches also
You can analyze your power data with the free version of TrainingPeaks, there are just a few charts that are missing but most of it is there. If you want to try the Premium version for 14 days free DM me for a code.
Thank you for all the help! I downloaded Golden Cheetah, and like it. The only plus I would see for Training Peaks is that I don’t have to download my training to several different sites.