I have the free app on my iPhone and watch and wish I could get notifications without paying for the ability to see if I like the full version. A limited-time full feature trial period would be nice. The reason I wanted the app was more to remind me to drink every so often more than keep track of the water on anything more than a daily basis. And clearly after having the app and not drinking much anyway because I get busy and forget and the day has ended, notifications is something I feel I would definitely benefit from.
I briefly looked over their user conditions and I have no desire to have my "statistics" anonymous or otherwise blasted to any social media kind of thing. Don't care for having to provide an email address either. Just let me buy the app and update through the AppStore when a new version comes out. Not interested in sharing my personal information at all. So thinking this app will be coming off my phone and watch soon.
I do have the app loaded as a Glance on my watch and when I go out for a meal or get a coffee try to remember to sit down and log the amount when I get it. Otherwise I'm more likely to get distracted when I'm leaving and forget to log it. I don't care for how the Glances view currently works on the watch, as each time I try to touch the water bottle it registers a new level of liquid even if I don't touch the + area of the bottle. Sometimes I am just trying to swipe the Glance and instead it registers more water and then I have to then go to my phone app to correct the error. A force touch to be able to correct amounts on the watch would be nice. Also noticed that when I changed the theme from water bottle view to the glass view, it doesn't make that change on the watch Glance. The app does have some nice features, has a clean uncluttered look to it, but not sure it's for me.