My $0.02 of going to SV...
+ Networking
+ Networking some more!
+ More chance of random meetings with people who can/will help you.
+ Vibrant community
+ Continuous critique / constructive criticism from learned
others (esp in startup community)
+ Motivation through environment
+ Sunshine (and good weather almost all year round)
+ Parties held by other startups and tech companies
+ "Cool" factor of being in SV
+ Change of scene from where you spent most/lots of your life (its good to travel and work in various places)
+ Lots of tech events more accessible in USA
- Losing focus from product development to relocation issues
- Losing time getting to market
- Time & effort to move (find accommodation, offices, visas)
- Initial costs & expenditure (Can spend on product instead)
- Leaving friends & family
- Shifting equipment (servers, printers, monitors, etc) unless hosted online or cheaper to (re)buy/replicate in SV.
...so basically I would say if you are able to go, then go. Also I have never met antone who regretted going but have met several people who have regretted not going.