I made a Breton with Spell absorbtion in General. Seems to me that the spell is either resisted or not, but never absorbed. I loaded many times to try it out. Only creatures yet to cast spells on me are imps, and always in dungeons. Maybe some worse spells will be absorbed? I've used Spell Absorbtion before and it has always worked ok. But, I picked In Darkness every time previously.

And yes, my mana was not full, if that counts.

Edit: of course I'm talking about TES2, but you knew that right?

How's your willpower? The spell absorption advantage uses that attribute to base your chances on snagging the spell or not.

Was about 60. I think I should have seen at least one absorbtion... But I already made a new character without absorb. I'll handle it with an item later
Breton with high WIL survives spells ok.