Namath was not the best QB of all time but he is a lot better than Mecca and many with the same line of thinking would have you believe. He did win 2 MVP's, a super bowl MVP, made the pro bowl several times, gameplanned/won the most important Super Bowl in NFL history and - like dabomb intelligently explained - he was a gunslinger back in the day when west coast offenses and spread formations hadn't even been imagined yet. He was pretty good at Alabama too.
Finally, his career numbers would look a lot different had he not succumbed to countless knee injuries and the subsequent knee surgeries. He was an incredible athlete and one of the games first and most gifted scramblers. Back in those days teams didn't gameplan for the Jets, they gameplanned for Namath.
But I guess you could ignore the era he played in and just look at his TD:INT ratio if you think that's how you evaluate a QB's value. In John Elway's first 10 years in the league he had a ratio of 158 touchdowns and 157 interceptions. He must've stunk.