The measure of an athlete is usually determined based on an examination of the player's career statistics. In the case of the three players mentioned, the highest career pass completion percentage belonged to Manning at 65%. However, both Roethlisberger and Brady had a career pass completion percentage of around 63%. This demonstrates, at least from the level of statistics, that all three quarterbacks are of roughly equivalent levels of competence, and therefore that Roethlisberger is on the same level as Manning or Brady.
Don't get me wrong Ben Roethlisberger is a good quarterback but he just isn't able to sustain the same level each week. He can be extremely good one week and terrible the other week. He is just too unpredictable, but when you see Peyton Manning or Tom Brady play you know that they are going to sustain the same level they have been playing at.
Roethlisberger has undoubtedly played very well and drawn significant critical acclaim in recent weeks but once again the press risk overly praising the individual of the moment. Whether this be for positive or negative reasons the press single out the extraordinary over the consistent. Come the end of the season then look back on the year, and team, as a whole.
Any time an athlete gives the kind of high-level performance that Ben Roethlisberger has given over the last two games, it's tempting to elevate them to the level of an all-time elite player. Sure, the record he set is extremely impressive, and has yet to be matched by either Brady or Manning. But being an elite athlete means performing at a high level consistently, and while Roethlisberger has played at a good or at least passable level consistently for a long time, this is not the same thing as the feats accomplished by Manning and Brady.
No, Ben Roethlisberger is not an elite quarterback on the same level as Peyton Manning or Tom Brady. Ben Roethlisberger wins because of his team, and if the team is playing poorly he cannot overcome it by himself. Peyton Manning and Tom Brady win despite their teams, and can overcome just about any challenge caused by their teams lack of experience and talent.