There are no leaders. Every other month a new LLM model comes out and it outperforms the previous ones by a small margin, the benchmarks always look good (probably because the models are trained on the answers) but then in practice they are basically indistinguishable from the previous ones (take GPT4 vs 5). We've been in this loop since around the release of ChatGPT 4 where all the main players started this cycle.

The biggest strides in the last 6-8 months have been in generative AIs, specifically for animation.