I have enjoyed many Harman Kardon speakers and audio gear over the years, starting with the cheap yet high-quality 2.0 mini computer speakers they released many years ago. Every since then, I have been hooked. So far, I have owned the Onyx 5, Go + Play 2, Citation 300, Citation 500, Aura Studio 2, and the SOHO wireless headphones, which is the only Harman product I find inferior. Otherwise, each and every Harman product I have owned has been a pleasure, and now this Aura Studio 3 is no different.
The first comparison I will do is with the Aura Studio 2. As far as specifications go, the main difference is with the woofer, which is now bigger and outputs and incredible 100 watts RMS, up from 30 watts from versions 1 and 2. My Aura Studio 2 already has room-filling sound and chest-thumping bass, but the levels the 3 can output is truly ridiculous. Most times I leave the volume at around 30 percent, and rarely do I go over 50%. Mind you I have this speaker in the living room of my modest 70 sqm(~750 sqft) 2/2 condo. I have tested it at 100%, but it was simply too loud and rattled the walls like a small tremor. This speaker, like the Aura 2, is more bass-oriented than other Harman speakers - really good and satisfying in the lows and mids, but a bit warm on the highs.
The other noticeable difference lies in the aesthetics, where the 3 rids of the vertical tube design of the first 2 predecessors. The lighting system is now more robust and pronounced, as opposed to a more subdued and chik glow of the 2. So as far as looks go, I still prefer my older version 2. The one downside of the tube design is that dust and anything that can fit down the tube will do so, and would be impossible to get out. Therefore, I had to buy a cover for it to keep out the dust when it's not in use. I got the one that looks like cat ears - yes, that is a real product.
Other quick comparisons are: The sound is similar to the Onyx 5, but power wise the Aura 3 blows it out of the water. The Aura 3 is also more powerful than the Citation 300(100 watts total RMS), but not as much as the Citation 500, which outputs an astounding 200 watts. Out of all my speakers, the Aura 3 has the most bass, followed by the Citation 500. The looks are top 3, only superceded by the Aura 2, and the Go + Play 2, which is my overall favorite speaker, because also for its most balanced sound, and portability.
Overall, while the Aura 3 compromises some aesthetics, it more than makes up for it in the sound department, and is now my second favorite speaker. I have now replaced the Aura 2's place in the living room, and sent it to my main bedroom. The Onyx 5 stays in the guest bedroom, while I use the Go + Play 2 pretty much everywhere(even in the bathroom on the john or in the shower). The Citation speakers I gave to my brother and parents, as I don't care for its aesthetics much. So if you had to choose between Harman Kardon speakers that have to be plugged in, I would definitely recommend the Aura Studio 3. It's 360-degree sound set-up makes it more than capable in any situation, especially for younger people who just want an all-in-one, simple set-up. For the more refined, there's always the Citation Tower speakers, and for everyone else, just get the Go + Play 2.
To be honest, I am jaded towards Harman Kardon speakers. Besides the SOHO Wireless headphones, they have never let me down. I can vouch for their quality, so find one that best fits your budget, and enjoy!