I may have been ambiguous but I am saying if you work somewhere (pre IPO) and you can see their killing it, on fire, and are seeing a truth other companies can't see then you know (perhaps doing some more research on public info) that it is a good buy.

Also for private companies you often get an all hands with financials, sales info, strategy etc.

The bet here is: this company isn't just lucky they have a killer system. You would get shares privately if possible. Even at IPO at a higher price, knowing they are kickass you can buy then.