In reply to moco:
Depends what else you plan to do. When we were there we climbed Iliniza Sur by the standard route, which goes at AD ish, and I was glad to have two axes, specifically for the short mixed gully low down as you access the face... thought this, along with Illiniza Norte, was well worth doing (poss as acclimatization for Cotopaxi).
Cheers,
Will