This could have changed in the last few years, but I think rg does tend to (sometimes significantly) outperform ag, see the author's benchmarks [0].

0: https://blog.burntsushi.net/ripgrep/#code-search-benchmarks

>much better single file performance, better large-repo performance and real Unicode support that doesn't slow way down

By ripgrep's dev (https://news.ycombinator.com/item?id=12567484).

The Silver Searcher appears to be if not dead then certainly resting.