On the other hand, at YC, when we needed help with our Series A, we got to talk to James Lindenbaum of Heroku, who taught us the ins-and-outs. When we needed to launch, we could talk to Alexis Ohanian who created Reddit (and interviewed us) and knows a thing or two about launching consumer sites. YC batchmates help each other and pay it forward when we become alums.
Few people do it these days for the money itself. One trend we see of late is companies who have already raised seed rounds, often from already prominent angel investors, opt to go through YC because it's a multiplier on their ability to execute -- they're more motivated, they focus more on the right things, have access to a hugely powerful network of alums, make deep lasting connections with batchmates, and then get a multiplier on their valuation at Demo Day.
I don't see age as the determining factor. Even for people who already have networks (I was an early engineer at Palantir, Stanford grad) it was useful to greatly increase the number of smart people I knew and trusted. (See Metcalfe's law.)
When it's viewed that way-- as not a fundraiser but a high-power incubator-- YC isn't a bad deal if you can capitalize on those synergies.
I have a lot of respect for Paul Graham and his Lisp advocacy in the mid-2000s can't be underestimated for its positive effect on programming. It was his essays that got me interested in Python, then Lisp and Ocaml, then Clojure and Scala. I'd certainly consider YC if I was sure I'd get a lot of personal attention from people like him.
The point is that no one really thought "22 year olds" were capable of making an economic impact before YC came along. Hence, someone with the simple idea to say "Hey, we should give 22 year olds this deal" created an employment impact on the economy as big as Facebook. The more people that come up with new funding models like YC that actually work, the better we'll all be.
In a vacuum, the trade works best for young founding teams and the value decreases as the team gets older (age typically does correlate with your leveragable network size).
Also, doing a talent scan for a startup concept. Possibly a Hail Mary pass because I don't know if anyone can meet the standards for the business co-founder, but worth a shot. http://michaelochurch.wordpress.com/2013/04/23/seeking-co-fo...
(NB. On the NLP for code quality analysis front: there's a startup {well, going a couple of years now, so now exactly startup} in Oxford that's been doing something related: http://semmle.com/ code quality analysis is supposed to be one of the selling points of their product.)