I don’t have a strong opinion because I’ve never used Babylon.

However, I’ll echo the sibling comment here. I used Three.js and had some problems exporting it into my TypeScript project (using the DefinitelyTyped repo for type definitions). It eventually worked with a dumb js file that I copied over from Three and edited myself to make the export work in my project. This was in mid-2019.

Anyway, after getting that all working and moving on, I realized I should have at least tried Babylon because the code looked far more suitable for a TypeScript project. I never got around to porting over because it wasn’t crucial for my project, and Three was already working.

Based on that experience and the fact that I prefer ts, if I work on another project with 3D rendering in the browser, I’ll try Babylon.