BezelMouse vs Universal Control
Built into macOS and iPadOS, and free. Every device must be signed in to the same Apple Account with two-factor authentication, and it links one Mac with up to two other devices. It's the right choice if all your Macs are yours and you only need two of them. BezelMouse pairs with a code instead, so a managed work laptop can sit beside a personal Mac, and any number of Macs can join.
BezelMouse vs ShareMouse
A long-standing Windows and Mac tool. Its free edition covers two computers without clipboard or file sharing; Standard ($99.95) adds both for two computers, and Pro ($149.95) goes up to nine. BezelMouse is Mac only, and puts that focus into things ShareMouse doesn't document: browser tabs, trackpad gestures, media keys and files that move when pasted.
BezelMouse vs Synergy
Cross-platform, with a server computer that the others connect to as clients, and an account for licensing. Synergy 3 costs $15, $19 or $29 once, for 3, 5 or 15 computers; encryption starts at the $19 edition. Good if you mix Windows, Mac and Linux. BezelMouse has no server: every Mac is equal, and there's nothing to sign in to.
BezelMouse vs Barrier
Free and open source, from the same lineage as Synergy, and cross-platform. It shares the keyboard, mouse and clipboard but not files, and the project sees little maintenance. BezelMouse is a maintained Mac app with file, tab and gesture sharing, for a one-time price.
BezelMouse vs SteerMouse
The remapper Mac people reach for, and deep on one Mac: buttons per app, cursor speed and acceleration curves, chords, for $19.99 once. It sees the mouse plugged into the Mac it runs on, and only that Mac. BezelMouse's remapping is one setup per mouse that works on every Mac the pointer reaches, and it comes with the crossing and the Dock rather than instead of them.
BezelMouse vs uBar
The Dock replacement for one Mac, and the one to beat: a taskbar layout, window previews, years of options, for $30 once. It knows nothing about other Macs. BezelDock is the newer take on the same job, and in BezelMouse the Dock holds every Mac's apps, badges and all, and Command-Tab crosses with it.