Sorry to hear that, Sam.... Yeah, NHibernate gets a lot of hype, but the thing with data-access technology is that it has to work always, everywhere, in all situations and shouldn't have any surprises. Though I think NHibernate isn't going forward as much as it did before, as key people left.
Your team mates, are they also fed up with NH or do they still love the random issues no-one knows how to fix?