I'm amazed TickTick isn't better-known. I've used pretty much every To Do available, and spent years going back and forth between OmniFocus and Things. Both have strengths and Things 3 is very good, but TickTick has ease-of-use, attractively simple interface (with plenty of flexibility under the hood), and a faultless sync to iOS. It also allows the one thing that was the eventual dealbreaker for me with Things: setting up a monthly recurring reminder on, say, the 15th of the month, that doesn't get pulled forward for the following iteration if you choose to do it on the 13th one time.
Great app, reasonably priced. Shame it doesn't update internally (you have to download the updates), but otherwise, extremely solid.