I'm not too sure if it is worth it. The talks will be posted online. The total amount of time that you have to network is only about 3 hours. I don't think the event is any more or less of a networking opportunity than any other meetup or conference in Silicon Valley.

I do think, however, that it's useful to visit SV and network at meetups and conferences in general. So I think going to Startup School requires a little more advance planning in the future. I think the best thing to do would be to plan a several week-long networking trip to SV that happens to coincide with Startup School (and for it to be affordable, the trip would have to be booked well before acceptances are sent out. That being said, Startup School is not very selective as long as you are an engineer).