Both are nice, comparably priced.
Banana Beach has a courtyard pool but is located a little further from San Pedro. There are more units there, so if you enjoy meeting other travelers, that might be a factor.
Carribean Villas has a lovely, natural arboretum-like area, a planned fish habitat off its pier and is a little closer to San Pedro (easy walking distance (even at night) to some very good eating establishments.