I received the Soundlink Mini for Christmas this year. I haven't had the time to do a lot of audio testing with it, but for me it's just ok. I have other hifi equipment around my home and intend on using this in the barn or basement while doing projects.
Not having used it too much yet, I can say the sound is decently impressive for its small size. Highs aren't as crisp as I would have expected with the small drivers, with most of the sound being in the mid-range area and bass. Speaking of which, the bass is acceptable and much more than on other small BT speakers I've played with (which has been few).
One thing to note with BT speakers is that they tend to have a small audio delay if using it with videos. I tested mine with my iPad watching some movies at my desk while working, and granted I'm OCD, I did notice the audio being off by a few milliseconds. Not enough to really be bothersome, but enough to know.
If you're looking at BT speakers, test a few out if you can in person. I really wish the Bose unit had speakerphone built in.
I'm currently backing a Kickstarter campaign for a BT speaker. These might be right up your alley. Search for "HiddenRadio2" on Kickstarter and check out those speakers. The ability to bridge multiple units would probably work well in a small apartment.