This app is excellent. It's very simple to use, integrates with the Apple Watch (so the reminders appear on my wrist), and even has a feature that seems like it might be fluff, but really is useful, in that you can customize the appearance of the pill icon that shows up with your notification, reminding you which pill it is that you're taking.
Most important about it is that it keeps all of the data about your medications ON YOUR PHONE; it doesn't transmit that data anywhere (aside from your paired Apple Watch). The app doesn't require you to sign up for some web service that "helps" monitor your medication history, but also reserves the right to farm your data off to a third party; no, Pill Watch doesn't require that at all.
The only shortcoming is that you can't set medications for weekly dosage, as opposed to daily. I wrote to the developer who responded a couple hours later telling me that this feature will be added in a future release. Nice to have a responsive developer.
Yeah, it's a couple bucks, but really to be reminded to take your medications on schedule, and to have your data remain private, it's absolutely worth every penny.