Is Stanford summer session worth it?

I just got the acceptance of Stanford pre-collegiate summer institute. But I am not sure if it is the right place to go for 3 weeks in my summer. I never expect to be accepted, but now I have to decide before next Wednesday whether or not I should go. I am also accepted by HongKong University’s math program and still waiting for other 2 school’s decisions. If someone has been to this program before, please please please give me some information about it. Thanks