For: A massive network of people you can draw on that surpasses literally anything you could build yourself. A decent chunk of money.

Against: Giving up a bit of equity, but if you're precious about that you wouldn't be considering YC.

It ultimately depends.

Only if the startup idea you are raising for is worth it, which now matters more than ever as execution is going to zero.

If that doesn't bother you and you need the cash now, then in summary:

   For: Access to bookface network (secret network for YC founders and mentors).

   Against: Depends on the terms, maybe not good if you mess up the cap table allocation.

If you don't mind the risk for a small amount of equity then you might as well do it before AGI arrives.