get certified here. The instruction will be better, as it wont be as suited for the tourist. If you get certified overseas, its going to be hit or miss. They know you probably wont come back to that country or shop, so they will probably teach you to the very minimum.
Plus, who wants to spend they vacation in class.
If you get certified out here, and do you open water dives in monterey, you will learn a lot more. There is way more life in the monterey bay, than almost any other warm water dive you will do. I've been to mexico and hawaii, and the diving in monterey trumps all.
Diving in monterey will teach you a lot more with your equipment, and how to get used to diving rough areas. IF you learn to dive in monterey, and you continue to dive here...you can dive anywhere.