To say Manning is overated is just ignortant. He is a well composed guy on and off the field, as far as I know, he is the ONLY qb in the NFL that is allowed to call plays from scrimmage whenever he so wishes. Plus, he has already broke several records and is on his way to break a few more.
From wikipedia...
Manning holds several NFL passing records, including: Touchdown passes in a single season (49 in 2004)[2], most consecutive seasons with over 4,000 yards passing (6 from 1999 through 2004)[3], and most seasons with 4,000 or more yards passing in a career (7)[4]. His career 94.4 passing rating in the NFL ranks first among active QB's with at least 1,500 passing attempts, and second all-time to Steve Young's 96.8. Manning has thrown for 275 touchdowns in his career (ranking him seventh all-time), and has thrown for a total of 37,586 yards in his career (ranking him thirteenth all-time). [5