yes it is the instructor. That said PADI in a nutshell puts it like this "you as an instructor follow these guidelines to the letter and heaven forbid something happens, its not you on trial, its us. However, you omit anything from your class or ADD anything to your class, we wont stand behind you." You may find a good instructor through the evil empire, however unless I knew someone specifically I would NOT get training there. Most large PADI shops teach you in two weekends. Sorry, I don't think the majority of people are that competent in two weekends. That is basically one long day or two short days in a pool, and one weekend diving.
My own personal feelings, I dread getting on a dive boat if it is chartered by SC. Usually they have the worst divers, and pretty crappy DMs. Seems to me most people that take lessons from SC are the type of people that don't really do any research, they just want a quick and easy cert and are pretty oblivious to their surroundings. (sounds harsh but my observations of SC charters are shared by many others) The classes are usually large classes so the students get minimal one on one time. And the instrucotrs tell the students to "kneel on the bottom" Fricken brilliant!!!!! Instead of putting in time in the pool so the students can learn some basic buoyancy skills, put a dozen people in the water where they are all waving their arms and legs, put them on a sand bed and soon there is no vizability......
Sorry for the rant, one other thing you need to ask yourself; how often are you going to dive. Are you going to be a WWW (warm water wussie) only diving every other year or so on vacation, or are you going to get your own wet or dry suit and start hitting the lakes and driving to the coast every other weekend. If you lonly log 5 dives a year, SC will probably be a fine place to learn. If you think you want to get into wreck diving, cave diving, deep diving, learning how to plan deco dives or anything other than swimming with your hands and looking for nemo I highly recommend taking GUE fundamentals of better diving. You dont have to get into wearing steel doubles with an HID can light, but you are taught such skills as using your head instead of relying on a computer. Yes I can look at my watch and tell you how much air I have left, I know how much air I use, I know how deep I have been for how long, so it is a simple math problem. You learn how to position yourself in the water, hint: it is not at a 45 degree angle with your legs rototilling the bottom like you see in all the photos with long hoses with gauges dragging over the corals. You learn how to use more efficent kicks than flutter kick wich pushes water up and down rather than straight back. How about this, you can learn how to swim backwards so you when you swim to close to something you dont have to use your hands to back up or swim in a circle for a second try.
There are some people with attitude regarding GUE, mostly online bs. I dive quite a bit, almost all my dive mates are GUE and are as a rule a bunch of good guys who help new divers.
something else, if you cant find a really good instructor, get certified and find a good diving mentor who can take you out and show you all the things SC didn't teach you. If you have any questions you can PM me.
HTH