i've done both and enjoyed both!
the 1/2 day package facial/manicure/pedicure/spa wasn't that great to be honest, the manicure and pedicure were just a quick file and paint none of the soaking cuticle stuff.
I had the pregnancy massage and it was fab.
i have also been and just used the spa, the peace and tranquility and the complete lack of children is divine, plus they bring you hot drinks with a lovely little cakey thingy all inc in entry price.