I’ve done the chest strap, a FitBit running watch, a Garmin 235, and Apple watches over the years. I will say that they all work about as well as each other, most of the time. There wasn’t any difference between my strap and my Apple Watch or FitBit. The Garmin 235 running watch seemed to be most accurate for distance, but, when it was really cold out, the heart rate got a little wonky. I never had that issue with the strap, the Apple Watch, or the FitBit. I highly recommend the Apple Watch, for a few reasons: 1) you can get a model that you can use as a phone. You can call for help if you have an issue. 2) Your loved ones can also track your location with the Apple Watch (if you allow them). 3) you can check your oxygen saturation with Apple Watch (good tool if you have heart issues. 4) Apple Watch can detect arrhythmia. 5) Apple Watch can be set up to call family or 911 if you suffer a fall. 6) Apple Watch will calculate your estimated VO2 MAX, which can be helpful if you are having heart and lung issues (mine dropped like a rock when I had a cold - or maybe COVID - a couple months back, and is just now starting to recover).
Yes, they are expensive, but they are fantastic tools to have. For about 4 years, I ran with both Apple Watch and Garmin. By the time the Garmin died, Apple had come out with all of these features, and I got older, so the more accurate distance measurement (IMHO) of the Garmin are less important to me, but the heart/lung/oxygen measuring features as well as the ability to call and be tracked are MUCH more important to me now. YMMV, but these are reasons we have them (wife started having seizures a few years ago, and this gave me the peace of mind I needed for her to go running without me unduly worrying).
