They are both fantastic. We are DVC members at both resorts and have two young DDs we have been taking since they were babies in strollers. It really comes down to the vibe you are looking for. The pools both have splash areas at the pools and the slides at both are pretty cool. I don't think my kids could pick a favorite between them (except maybe the last one they were on). If you require bigger than a studio, then that would put BLT up for the win. Unless you plan to rent enough points for a bungalow at the Poly, you would only have studios. That would be the biggest difference besides theming I think.