I've been using Arccos for a couple of years and I'm a fan. It did take a little learning to get started, but I've had very few issues using both an iphone and the link. I've only used an apple watch once and have not learned how to use that within the flow of the round. My son uses a samsung phone and definitely has ore missed shots and shots on the incorrect holes, but I've never had that issue with an iphone. I typically check my phone between holes, mostly to adjust pin placements and add correct number of putts. It is not accurate with putts for me (sometimes too few, sometimes too many). I'm definitely a better player because of the data. Now you don't just feel like you were driving is better a few weeks ago, you have data to support your hunch.
Honestly, I didn't notice a difference with the phone or link. Both pick up nearly all my shots and neither were better or worse picking up putts. Phone in the left pocket always worked for me, but I'm sure there are differences between models of phones.