My last boss, CTO of a fairly small YC start-up, was ex-blizzard (SCII player matching infrastructure + D3 launch) and he's hand's down the most amazingly technically skilled person I've ever worked with. He did have a few brutal stories from the trenches at Blizzard, but to be 100% honest I'd probably take a 15% pay cut there vs a typical large SV company just based on what I heard (and saw).