Phipps is a great venue for a romantic date-night, or a casual afternoon with friends. I make sure I visit during season changes (especially Christmas when the train set and winter flower show begins). The outdoor space, including the bonsai garden, are worth visiting for in the summer. My favorite room is the desert, and the butterfly room in the summer. Phipps has a cute gift shop and a lovely cafe. It is easy to spend 2-3 hours walking the grounds, or 1 hour if you are a repeat visitor who just wants to take in the special exhibits.
The outdoor garden (facing the Cathedral of Learning) is a beautiful spot for events too. The pricing is reasonable and events staff are extremely helpful/accommodating.