Earth's Children/YMMV

Canon Sue: Ayla; Jondalar as well, to a lesser extent. This is somewhat justified considering that both of them have traveled alone or with extremely limited support for a number of years, and you'd have to turn into some sort of God Mode Sue to survive that in the Ice Ages. But throwing Fixer Sue and Black Hole Sue traits on Ayla is largely agreed to have gone too far. Your heroine does not have to be perceived as the incarnation of the Great Earth Mother to be interesting. The technologies they invent together are each described with a plausible thought process, but the sheer number of them is only believable if you take them to be allegorical characters.
Complete Monster:
- Broud. Prehistoric societies cannot afford leaders so hateful they are willing to ruin the clan just to spite some woman.
- Attaroa is sadistic, insane, vicious, and so impractical that she tries to commit Gendercide and honestly thinks it'll make her camp more prosperous. She's depicted as having pretty much no redeeming features. S'Armina claims that in her own way, Attaroa loved her adopted son... but that didn't stop her from having him brutally crippled at puberty, then throwing him in the stockade.
First Installment Wins: Even hardcore fans of the whole series agree on this.
Jerkass Woobie: Brukeval
Narm: "HE'S MAKING MY BABY" sent the scene from disturbing to hysterical.
Seasonal Rot: Many readers considered Shelters of Stone to be the weakest book of the series until The Land of Painted Caves was released and lowered the bar.
Sequelitis: Clan Of The Cave Bear was an excellent book. The rot began to creep in in The Valley Of Horses, and it was all downhill from there as Ayla became more and more unbearable and Jondalar became more and more unlikable, and the entire series disintegrated into a somewhat ridiculous, overwrought Stone Age bodice-ripper. Or loincloth ripper.
Squick: Some of the sex scenes have this effect on some of the readers.