Didn't really care for the first film. I thought I'd like it (and certain real life friends of mine even said it was something I'd enjoy), but I thought the plot was far too flimsy. I wanted there to be a more exciting, believable interesting explanation for why they woke up in that crazy situation. Instead of feeling like it unfolded organically, it felt retconned. I could picture the writers sitting around thinking of wacky things for them to wake up and find, but fitting the explanation for those events into the narrative didn't appear to be a top concern
On that note (and keeping in mind the fact I'm not anti-Gibson), I can't say I'm too interested in the sequel. The cameo would be bizarre and fascinating on a certain level, but it wouldn't really get me any more excited about H2 as a film than I already was (which is to say, not at all excited)