Lol. He was the "Head of Product Management for Cloud AI Verticals". I believe that means an L7 or L7.5 PM at Cloud. That's cool and all, but not really drawing top talent away from Silicon Valley. Call me when the senior principal research scientists start leaving.
I think the tech talent at Two Sigma is pretty solid. The pay is comparable to top tech firms but there are more opportunities to get promoted to higher-levels (like L6 & L7 equivalents at GOOG). In general people seem to move both ways, some going to Goog, some coming from there, and some going there and coming back to Two Sigma after a couple years (and vice versa)