I won't list names, but there's one team that was rejected from this batch that had raised a series A (from a good VC) before any of the teams from the batch did.

The fundamental thing is that you've got to want to start a startup, rather than to be in YC -- if you want to start a startup YC can be something along that path, but far and away most of the startups that have succeeded have done so without YC, so that's obviously a well-worn path to success.