After reading a bunch of articles (and thinking back on campaigns), I think I would put them in tiers like this (feel free to provide any counter-arguments to improve it).
This is my thinking about non-archetyped classes at this point.
Tier 1: Wizard, Half-Elven Oracle, Half-Elven Sorcerer, Druid(2?)
Tier 2: Cleric, Oracle, Sorcerer, Summoner(1?), Witch(1?)
Tier 3: Alchemist, Bard, Inquisitor, Magus, Paladin, Ranger
Tier 4: Fighter, Barbarian, Cavalier (5?)
Tier 5: Rogue
Tier 6: Aristocrat, Commoner, Expert, Monk, Warrior
I've never played with Psionics, so I can't comment on where those classes fit.
I could maybe see switching druid to 2, and summoner/witch to 1.
Other people seem to rate the Cavalier low, but I'm not quite sure why. It seems to be in the same ballpark as the Fighter and Barbarian. My only experience with one was a Houndmaster, which I would have ranked at a high 3 (Teamwork Feats + Two Wolf Companions (dogs) + Leadership (Advanced Worg Fighter)).
I hope to hear additional comments from others with their opinions on how they would rank the classes and why, and if anyone has any constructive criticism or input for the tiers I just put up, I'm interested in hearing them.