To me they are real people, they think and act and react to life like real people, and they have an enormous amount of depth.
I love Mieville, and Erikson, and a bunch of other fantasy/sci-fi writers, but not one of them can even come close to matching Martin's characters IMHO.
Mieville is a great world-builder, and he has some bloody awesome ideas, but I always feel distanced from his characters. Same goes for a lot of Erikson's characters, to a lesser extent.
And as for Jordan...any good characters that he did have when WoT started have since turned into cardboard caricatures of themselves in the last 3 or 4 books. And he can't write believable female characters at all. Every one of them thinks and acts and speaks the same way, and it ain't like any women I've ever met (perhaps I've been lucky

In short, I don't think any other fantasy writer has characters that come close to Martin's. But thats just my opinion.