Very! It defaults to an automatic setting where it chooses the best settings for your picture. When I went to take sunsets, it changes automatically to sunset mode. When I was taking pictures of people, it automatically changed to portrait mode. It also comes with a very detailed owners manual to show you how to operate the more advanced functions. The 4th of July it changed to FIREWORKS mode, I didn't even know it had a fireworks mode! :)
I am not an avid photographer. I am using the camera for outdoor shots mostly. I have had this camera for almost a year and have had no major problems from drops. I would avoid potential problems with it for rockclimbing for example. Otherwise, fine.
I would say SOL. You may have broken the gasket on the rear door which may have caused a leak. I had an earlier version which went in about the same way you described with screen failure. I did not take mine underwater however. I would look into sturdier models which may have extended warranty periods. You should seek out other opinions. I did purchase this model again but will not subject it to water.