I have never liked the "Olympic medal" eras of comics as it breaks down after Bronze. What's after that? Tin? Dumb. It never made sense to me as a) It infers that everything after Golden is inferior when nothing could be further from the truth - from an art and storytelling perspective to the way the books are created and manufactured. b) The metal eras doesn't address what's next after maybe "dark" and that was almost 30 years ago and c) doesn't take into effect too much of the history of comics both in terms of publication content and editorial decisions.
I, myself, have taken some cues from the classifications of genres used in film studies which are: Primitive (or Pioneer), Classic (or Golden), Revisionist, Parody, Post-Modern, Nostalgic and modern (which is used as a sliding scale to whatever is the "current" era). I've applied this to comic books and came up with the following classification system*:
Primitive: 0 - 1935 (Proto-comics to New Fun #1)
Classic (or Golden): 1935 to 1952 (Action Comics #1, Detective Comics #1, etc.)
Revisionist (or Atomic): 1953 - 1970 (with the passing of the Comic Code, Incredible Science Fiction #1, Showcase #4, Fantastic Four #1, ZAP #1, etc.)
Post-Modern (or Super): 1971- 1985 (Green Arrow 85 , Amazing Spider-Man 96, Crisis on Infinite Earths)
Dark: 1986 - 1994 (Watchmen, Batman: The Dark Knight, Spawn )
Nostalgic: 1995 -2000 (Marvels, Astro City, Zero Hour, Starman)
Ultimate (or Marvel): 2001-2010 (Marvel Ultimate, Alias, Wolverine: Origin, Editorial changes at DC)
Post-Revisionist: 2011 - 2015 (Flashpoint, New 52, Marvel NOW!, Ms. Marvel)
Modern: 2016 - present (DC Rebirth, etc.)
Granted I realize that the "edges" of these eras aren't as clear as I'm making them out to be, but ya gotta draw the line somewhere! I'd love to hear your thoughts on this classification system of mine!
* I freely admit that my classification has a bias towards American superhero comics in general and DC published books in particular.