[...] the Beatles' demo tape had been "pretty lousy" and "very badly balanced" and contained "not very good songs" by "a rather raw group," Martin has recalled [...]Perhaps there is hope for me still.
In the beginning, Martin was tough on the group. "As composers, they didn't rate. They hadn't shown me that they could write anything at all," he told Melody Maker.
-Salon.com, article on George Martin
The article also quite rightly indicates the importance of the producer. Remember Bruce Springsteen singing about the million-dollar sound? That can also refer to the price of the producer.