I use both - when I was self coaching and now that I have a coach. I like the metrics more in training peaks and find it much easier to get the data I want, edit rides, etc. That being said, TR has the plans to make you faster. If you can only do one (and you don’t have a coach), it should be TR. Having both is a nice luxury, though.
With a coach, I guess I don’t really need TR anymore, but I still like the platform for doing workouts. I also like to support them for the amazing work they do on the podcast.