I mean, after YC, the second best startup accelerator, by the "if I didn't get into YC, which accelerator would I consider" metric. (SendGrid still tips the scales for historical performance in favor of TechStars, I guess)
Personally speaking from a Silicon Valley perspective (and having worked at a YC company before), 500 Startups is tied with TechStars on my list. I've never heard of any of the other accelerators on that list except AngelPad.
but it's true we are all chasing YC's tail currently.