I'm a stats and analytics guy. I like to use that as the "eye test" isn't always easy across eras. There may be guys that "look" better but stats, wins and championships don't lie in my eyes. Here's Part One of my list of the best quarterbacks ever.
Joe Montana
Montana not only won four Super Bowls, but he also posted 100+ QB ratings in an era when guys struggled to get to 90. This includes 1989 when Montana's 112.4 QB rating was 20 points higher than second place Boomer Esiason's 92.1. Montana also led the league in completion percentage five times. For players that retire prior to 2004, Montana has the second-highest career completion percentage (63.2%) to former backup and fellow Hall of Famer Steve Young (64.3%). Montana also is one of the few QB's to actually play better in the playoffs than the regular season as his career completion percentage (62.7%) is almost equal to his regular season number and his QB rating is actually 3.3 points higher.
Steve Young
Young typically doesn't get the recognition of guys like Montana, probably because he only won one Super Bowl. However, Young is possibly the greatest regular season QB ever. At the time he retired, Young was the all-time leader in completion percentage (64.3%), passer rating (96.8 to #2 Montana's 92.3) and tied with Dan Marino for the highest net yards per pass attempt (6.89) in a career. The knock on Young comes in the post-season where his completion percentage dipped 2.3 points (62.0%) and QB ratings dropped 11 points (85.8).
Dan Marino
Marino was the league's most prolific passer ever when he retired in 1999. When he hung up his cleats, Marino led the all-time lists in passes completed (4,967), pass attempts (8,358), passing yards (61,361) and passing touchdowns (420). Many regard Marino as the game's best all-time passer from a pure talent standpoint and from the talent he worked with on his team. However, Marino never won a Super Bowl, never led the league in completion percentage and led it only once in passer rating (108.4 in 1984). Outside of his first two years in the league, Marino only posted two QB ratings over 90.0 in his final 14 full seasons. Marino also dropped off considerably in the playoffs posting a passer rating that was 9.3 points lower than his career rating. Marino's completion percentage also dropped 3.4 points in the post-season (56.0%).