I went to Belize 2 yrs. ago and ended up staying at Mata Chica for 2 weeks. I think it's a great place. Depending on your needs, Mata Chica could be the best place in Ambergis Caye.
Mata Chica is ideal for people (mainly couples) who want R&R and be isolated from the rest of the world. It's very quiet and beautiful. The restaurant (Mambo) serves tasty dishes and the staff were nothing short of excellence. Of course w/ the advantage of being so far away from everything comes the disadvantage of waiting for water taxi and paying a bundle just to step away from Mata Chica.
My boyfriend and I are planning another trip to Belize in June. We're planning to stay at Portofino. I loved their website, but I didn't get enought info as to the accomodations or the location. If you end up staying at Portofino, could you please send me an email letting me know.
I'm trying to get people to send me or post recent pictures of Porofino (I'm still not sure about it).
Hope I helped somehow.