Lexvo is absolutely right: It's such a personal thing that you really just have to try one or two and go from there. If Things appeals to you, I can tell you that it's a great one to try. Things is one of my favorites, and I've tried a LOT of these apps over the years. Unless you have used one of these apps before, it's hard to even know what features will matter to you. For a few years I bounced from app to app until I found one that didn't leave me wishing for more. I liked Things enough that I'd be willing to give Things 3 another go to see if it would work as well for me as my current app. Others I really liked include Swipes, 2Do, and OmniFocus. I probably would have stayed with Omnifocus if they offered a Windows or a Web based application.
The one that I have stuck with the longest is TickTick. I've been using it for a couple years now. It is simple and elegant, but it also has some really powerful features (although you have to pay for the premium version to access some of them). I'm a premium subscriber, which runs 27.99 a year, but if I wasn't so obsessive about my Task list apps the free version would work for me just fine. TickTick is a Web-based solution with iOS and watchOS apps, so I can access it from my Windows PC, iPhone, iPad, and Apple Watch.
Whatever you use, make sure you use it regularly to get the most out of it. There are many different productivity methodologies out there, and many apps are built around the popular David Allen methodology called Getting Things Done (GTD). I read the book and it certainly helped, but I kind of developed my own habits that work for me. One thing I do try to keep from GTD is the weekly review. I try to plan both one day at a time and one week at a time. The weekly review helps me re-prioritize, and it also helps me clean up and delete the stuff that just no longer seems important enough. One of the problems I used to have was list rot: I'd keep adding and adding until the list because an overwhelming and depressing mess. Weekly reviews along with proper organization help avoid that.