Having worked as a designer in the past, I have tipped my toes into many tools and have experience in many of them. The market is dominated by Figma and Adobe XD, though there is Sketch, many people have moved on from it despite all of its efforts to keep up with the competition. It has to be said that all three tools are great, but still we're gonna review and compare the first two. They are pretty similar, but as always, the devil is in the details, and we're going to get into that today. I must also warn you: those are my thoughts and my opinion only. I used both tools for over a year, and run into some pros and cons for both, so they might not be too objective.
The first thing that I wanted to talk about is stability. When I started to use Adobe XD for a while, I was very impressed with how fluid it was, but... It crashed a lot for me. No matter how many times I reinstalled it or used a different device, it still crashed. This issue is fixed now, but it left me really confused nevertheless. Figma, on the other hand, was always a little bit sluggish here and there, but it's a whole lot more stable, almost never crashing. I work on Windows, so there are some problems: it seems to handle large projects pretty bad here. My colleagues with MacOS do not have the same problem, but I do, and it can get pretty freaky: I have 16 GB RAM, and it still runs out of it pretty quickly if I open some of our larger projects. You can't judge this part unbiased, I believe, but the clear winner for me is Figma here because the part of the big project is probably Windows' fault.
Adobe is only available as a downloadable app, allowing you to preview the projects in your browser only when you have a link. Figma, on the other hand, can be run from your browser without any limitations, which is awesome as hell! Both are available for all popular platforms, so it's a tie here. A little cool thing that works better with Figma though is the mobile app. It lets you stream your prototypes live on your device, so you can see how it will look like on your phone. It feels sluggish and unnatural on XD, so it's on a losing side here.
Figma was a game-changer here, there's no going around that fact. XD is still quite far behind on some features here and there, trying to keep up, or rather catch up. Collaboration was Figma's biggest advantage over Adobe, but the latter is getting closer and closer to its biggest competitor level. However, I don't think they will be able to match how effortlessly Figma does it: you still have to manually sync the project to the cloud and only then you can collaborate in real-time. The thing that bothers me a lot is that Adobe requires you to log in every time you want to look through some random project you were sent. Figma lets you look regardless. Another big con of XD is limited storage. You won't be able to create a lot of projects for free. And it still uses offline documents on default, saving them on your PC. It feels like a stone age for me after using Figma, which also has offline files (only if you want to save it manually), but it's entirely cloud-based on default. Collaboration with developers is also way better with Figma. Devs can easily preview the project and get all the dimensions and styles, download images along with icons, increasing the efficiency of their work significantly. It's a very big thing when you work in a full-cycle agency!
Now we can talk pricing. If you are a beginner designer or work on your own, Figma is a clear winner here. No limits with a free plan whatsoever — along with unlimited cloud storage. Limitations come when you start working with a team, especially when you will organize all the team files, projects, and things like these. It will cost $12 per editor/month to unlock all of the features. Other people aside from the assigned editors won't be able to edit anything, but all the viewing and exporting features will stay. You can just copy the project into your library with one click and edit something there if you'll need it though, that's one way around the limit. Adobe XD offer a week-long trial free of charge, and then costs $9.99 per month. The free version is pretty limited: you get 2 GB cloud storage only, which is really little, limited fonts, and limited editors. The Pro version unlocks all of that, but the cloud storage will still be capped, but at the 100 GB mark now.
What Should I Learn Then?
If you're just starting as a designer, you might want to try both and give them a fair trial. But my honest recommendation is Figma because it's the current future. The learning curve might be a little bit longer with it, but it's definitely worth it. Besides, if you started as a solo designer, it's completely free for you with no limits whatsoever. There's no harm in trying to do one project here and the other there so you can get the gist of what's better for you. Both tools are pretty widely used, so there won't be any problems with clients or something like that.