I strongly disagree. You should never join YC. Ideas/startups that require money to accelerate are bad. Just choose a better one.
Now this is my opinion. I start a startup to be my own boss and change the world on my OWN terms. Why the hell, should I go to YC to hire a boss?
To grow faster? To learn how to grow?
BULLSHITT! I can do both of those without their help -- call me arrogant, I don't care.