Koomot offers very clearly presented bike and hiking routes in a region of your choice. What's special is that apart from a kilometer count and estimated duration you will also find information about the road conditions and reviews with pictures to every part of the route.
When you have decided on a tour you can save it to your profile and start it at your convenience. It's also very easy to create your own route, should you feel like it. The downside is that you only have one region available for free, every additional one costs a one-off cost of 19,99€. You can save completed routes in your profile.
Bike Citizens is originaly a magazine and blog about urban bike culture, but their app also let's you plan trips and check out routes that other riders uploaded. Every city has it's own package containing maps and trips with marked sights and landmarks, along with short descriptions.
Sadly the layout of the app and the routes they offer not as accessible as they are in Komoot, as you can't plan routes in advance and save them and also they have no reviews.
The packages for individual cities can either be bought, or - which is an awesome feature - they can be unlocked by riding 100km within 30 days.
If you buy a Finn Phone-Mount you receive a voucher for one city-package for free.
Strave is, at least as we've gathered from our riders, mostly there to record your activites and save routes you've already done.
The coolest part is that every route is divided into smaller segments. While you're riding you can constantly compare yourself with all the other riders who did the route and special achievements are rewarded with trophies!
You can also find some suggested routes for different cities through the option "Locas Guides". Whether it's Albuquerque or Zürich, there are a lot of routes with points of special interest. Sadly this feature seems to only be available in the browser version so far.
So Strava might be more versatile to record your achievements and as a fitness tracker.