Previews are massive in Wayland
Whenever I preview files when using a Wayland session, the previews for many file types will be huge, often bigger than my screen. On an X11 session it displays in a sensible size centered on the screen, even when previewing rather large image files.
To be more specific, on Wayland most file types containing text will opening up in a full screen window for some reason, while the same file types will only be a small window in X11. Huge pictures, like a screenshot of my desktop, will be displayed way larger than their actual size and will be expanded past my screen borders. Again, not a problem in X11. Smaller pictures won't be blown up like that, but they will open up in the corner of my screen instead of nicely centered.
For what it's worth, I have a HIDPI display with 200% scaling. Using 100% scaling seems to let me avoid the overblown previews, but in a Wayland session they still open up in the corner of the screen instead of centered.