From a laymen perspective, I see David Sinclair as the clear leader in this field with actual lab results to back it up. https://sinclair.hms.harvard.edu/research I only remember Aubrey de Grey talking and presenting a lot but there wasn't the level of substance that seemed satisfactory to me. Ad hominem alert... Aubrey gives me the sensation of scratching a chalkboard with his strange social life and terrible hygiene but is obviously intelligent. In stark contrast...David has all the admirable hallmarks, socially and academically.

Substance really only matters to me but it is worth mentioning Aubrey's oddness as it seems quite extreme and entertaining. I think Aubrey's weirdness actually had the opposite effect of making me give him more credit of a potential mad genius than now seemingly deserved but maybe that will change.