The best practical benchmark I found is asking LLMs to research or speak on my field of expertise.
Real research needs several more levels of depth of contextual knowledge than the model is currently doing for any prompt. There is so much background information that people working in my field know. The model would have to first spend a ton of time taking in everything there is to know about the field and several related fields and then correlate the sources it found for the specific prompt with all of that.
At the current stage, this is not deep research but research that is remarkably shallow.
Reminds me of when Altman went to TSMC and bloviated about chip fabs to subject matter experts: https://www.tomshardware.com/tech-industry/tsmc-execs-allege...