Why not ugrep?

They are more or less equivalent. One has obscure feature X other has obscure feature Y, one is a bit faster on A, other is a bit faster on B, the defaults are a bit different, and one is written in Rust, the other in C++.

Pick the one you like, or both. I have both on my machine, and tend to use the one that does what I want with the least options. I also use GNU grep when I don't need the speed or features of either ug and rg.