Summary: I couldn't find a head to head comparison anywhere. Since the Zipp came out in October 2012 any comparisons were with the original SoundLink or SoundLink II, so for others wishing to compare, hear (sic) goes! Sound Quality: No contest, on balance. The Zipp is much more dynamic and detailed.
Summary: Amazing sound. Really top notch quality. The built is great too. Seems very durable and well made. Love the design. Really easy and flawless connection to all of the wireless devices. Work really good even at 60-70 ft.
Summary: Excellent built quality and the wool covers feel great. This speaker has a nice warm sound, with very good bass for its size. It's plenty loud to fill a room, but I haven't used it outside yet. It also really does seem omnidirectional.
Summary: What a great speaker. I had been looking for a really good wireless speaker for a while, and decided to take the plunge with this, due to the glowing reviews I'd read on What Hifi and in other publications. I'm really glad I did.
Summary: A great speaker delivering excellent room filling sound. Powerful, crisp, rich, and base in all the right places with enough power to fill the room and would rock any party - although I've not had it turned up to the max as I don't want my ears to bleed.
Summary: Nice sound for an AirPlay/Bluetooth speaker. Cleaner than Bose Soundock and 360 degree sound is good. Reviews say battery time is not good but I was working in the garden listening to music for 6 hours and it survived despite spec saying 4 hours....
Summary: I auditioned a wide range of wireless speakers from £120 - £900 before purchasing this. Needless to say, you get what you pay for, but its at around £300 where speakers start to exhibit hifi quality sound. On the Zipp, voices sound clear and natural.