Until some seconds ago when I was looking through one of the grammar section is test review book, I had long believed that they were (most of the time, but you know English always has those nicketypicketies that "no one" cares about) interchangeable.
Here is a example, where only "and" seems appropriate, according my book;
Because of her command of pathos, tragedy, and humor, George Eliotis considered to be a great English novelist.
This is the explanation it gives as to why "as well as" in place of "and" will be inappropriate:
The phrase as well as improperly connects the third item in a series humor to two earlier items...