I've been using onX Hunt for a few years now, and honestly, I can't imagine how I ever went without it. It has completely changed the game in my hunting and guiding. Yes it's great for setting stands, you can send pins and share with other hunters, yes you can upload photos of your locations and pin them on your map; but what really was game changing for me was offline maps.
Why? Because it means I don't need to carry a separate GPS. I can load a map onto my phone (bring a battery backup!) and head out into the Adirondack wilderness without any concern about knowing where I am, or where I need to be. When a buck is on the ground it means I can find the nearest road to get the buck out to. Also, when you're hunting deep in forever wild areas, its almost impossible to remember what you saw in one spot and where that spot was. Everything is either a beaver swamp, a spruce thicket, or a mountain. Not to mention that most of our hunting is in the snow, so there's almost no way to relate summer scouting to winter without a solid mapping app.
I couldn't possibly be happier with onX Hunt. Now that they've added the photo option for pins, and weather station info, it's even better. I recommend it to everyone, and I would never hunt without it.