How old are your twins? "Relaxing" and "twins" are two words I've never seen in the same post - congratulations!

January is traditionally low to mid 60's in either location and the beaches are usually breezy. I'd say for variety of family activities & quality of beach, HB is a better fit. That said, as an adult looking to relax, I'd probably pick the PH. I think you're fine with either choice.