i have played beserker on the dc, but haven't read the manga. However, from what i gather, Guts is more psychotic next to Kratos.
as for coming back and fighting on from near death, say hello to Dante which always makes a come back from near death, Goku which actually comes back from death a lot, Ichigo who can be stabbed and have his soul taken over yet still manages to fight back.
Kratos wins it for me because he doesn't try, he actually does kill many gods, he goes through hell and back (lets face it, what can possibly be worse than hell?) and then he opens a can of woop ass on everything, yet remains in control of himself.
Since Guts cannot control himself, that automatically is a fail in a sense.