I now run a $XM SaaS (scale-up, not startup) growing at Y00%/annum. 100% bootstrapped with a healthy profit margin. Thanks YC.
The only thing I'd say that YC is good for is their network of existing startups. Then again, startups aren't the best customers IMO given that they die too much.
Advice is free on the internet as marketing material these days. And there are better VCs.