I use a Garmin Instinct. I probably wouldn't buy one just to use it for my Alpha, but I already had the watch when I upgraded to the Alpha so I use it. It is handy to look at my watch quick to see the direction my dogs at or the wrist vibrating when she's on point, but I wouldn't spend $200+ on that stuff alone.
I have the instinct as well. I like it for fitness and hiking. The tracking features are good with the Garmin app. I also use it with my alpha especially when the dogs on point. I can have both my hands free. It's especially nice in thick cover when your trying to move fast to the dog.
I pair an instinct to my alpha 100. I bought the watch specifically for that purpose and I am glad I did.
My alpha 100 stays strapped to my chest with the tone buttons accessible. I keep track of the dogs pretty much exclusively through the watch.
I hunt every weekend during our 4 month season plus on holidays and some vacation days. I also run the dogs on wild birds until April. I get a lot of use out of the watch and have my gun in both hands when walking into a point in high cover.
I have an Instinct. I like it. I really don't need any of the bells and whistles. Sometimes it seems to have a mind of its own and I have trouble getting back to the time screen. Now, in defense of the watch, I've never really read all of the directions. I just don't have any use for all of the GPS and trail stuff. It is easy to switch back and forth from the dog screen. Pretty handy but I still find myself looking at the handheld some. Probably habit.