Both places are similar with respect to services and attention to detail. Pranamar is new, so the grounds are still developing. Accommodations are very nice but not as private as Florblanca because the gardens in Florblanca have had many years of growth to give each cabina lots of privacy. The beach at Pranamar is nicer and is close to a tidepool that is large enough to snorkel in. Florblanca's design is modern and Pranamar is more Balinese. Both places are very romantic settings and have a very 'zen-like', calming atmosphere.
If you are concerned with the fact you are traveling with children and unsure about a child-friendly atmosphere, perhaps you should also consider Villas Hermosas which is family/children friendly and just down the road from Pranamar.