I really like Dagger. I had a _lot_ of weird issues with Earthly, like edge cases. Dagger has been mostly solid.

It still has gaps. I don't think they've landed on the right model for CI. Like Earthly, their model is a CI runner + local cache. I believe a distributed cache (like Bazel) makes more sense.

If I were choosing between the two I'd personally always pick Dagger, but I think there is a strong argument for Earthly for simpler projects. If you're using multiple Earthfiles or a few hundred lines of Earthly, I think you've outgrown it.