I believe the first option would be the money, if are able to afford traveling abroad or entering a good Uni would depend on that, and of course nothing which costs money would be without a good reputation, so following the money would be reputation. Then comes the environment, like which country is possible for you to live in or if you got any relatives in a certain country where you would stay with them.
As for which certificate is better..it all depends on the Uni. If you are American..you don't have to travel overseas to have a higher value certificate when you have MIT, Yale or UMD in your country.