The scenario you describe is precisely why I like G+'s circles; every post and every photo shared is shared with a specific subset of my contacts. The vast majority of my posts on G+ are targeted at only a fraction of my friends.
Facebook had this functionality for years before G+ launched and is built into the status update box.
Plus you can have closed user groups on Facebook. They work well....
I'm well aware of that, but the UI is nowhere near as convenient and targeted sharing doesn't play as central a role. "Circles" was the major differentiating feature when G+ launched.