Hi, I have a Garmin Fenix 6 Pro and before that a 945. They have some really compelling features in the app and some excellent tracking abilities. Most of their flagship devices, even a generation back, will unlock more metrics than you could ever ask for as well as have the ability to be a primary activity tracker. With that said, it is user intensive. You can really deep dive the data but it can also be overwhelming.
I was a long holdout on a Whoop because I had the Garmin, but I finally tried it out and I am much more satisfied with the user experience. I still use my Garmin extensively, but the infographics and ease of use on Whoop’s app is brilliant. Those key performance indicators around recovery are served up in a way that makes sense. If you can resist getting too reliant on them to drive daily decisions, you can learn a lot about how you respond to different elements of training and lifestyle.
To be clear, you can get everything that whoop provides on a Garmin, it is more a matter of preference and engagement. I love parsing the data, but sometimes I just want an at-a-glance readout that I can use to reconcile how I feel with training decisions. Yesterday for example I felt like I was dragging all day. I had the inclination that a ride might drag me out of the funk, but I looked at my data and saw my heart rate, HRV and general sleep quality was abysmal. It took me less than 15 seconds to establish that I wasn’t just being a baby and really needed the rest so I took the day off. This morning my recovery is 90% with HRV, RHR and sleep looking fantastic! I am ready to work.
Just my experience, hope this helps 