I've tested a great many bluetooth speakers (non-portable, portable and ultra-portable) and headphones over the years. Although I'm clearly not an audiophile, I do enjoy the best sound - in the car, at home, in the office - and I have a lot of side-by-side listening to provide solid A/B feedback. I tend to test them out, return the ones that aren't good, keep those that are. And so I have.In the bigger bluetooth speaker area I like the Polk Woodbourne and Aiwa Exos-9 best. In the portable area I like the B&O Beolit 15 and absolutely LOVE the Klipsch KMC-3. Unfortunately, all of those except the Aiwa are discontinued. The ultra-portable category has been dominated in sound quality by the Bose Soundlink Mini / Mini II for more than 4 years - and that's for having tried a number of high-end competitors, including the Bowers & Wilkins T7 and KEF Gravity One, both of which were, frankly, abysmal in comparison to the Bose.Now, to the point: The B&O Beoplay A1. The biggest engineering challenge in a speaker this size, in my evaluation, is the ability to articulate bass. Many reviewers gravitate towards "it gets very loud" or "it doesn't get loud enough". I notice that - but frankly, don't care. I'm not buying a tiny speaker like the Bose or B&O to fill a gym or crank it out for a block party. It's a personal speaker - I use it on my desk, put it on the dresser in a hotel room while on business travel. Listen to music or movies at moderate volume. What I care about is, almost to the exclusion of everything else, the quality of sound, especially bass reproduction. Secondary considerations are construction quality and aesthetics, battery life, volumeB&O did a Good to Very Good job with this. It's small, it's pretty. You probably want to keep it in a pouch before you throw it in your backpack or suitcase, but it's definitely in the same volume/mass category as the Bose. See in the attached pics, different form factors but similar total size and weight. Both are naturally very well designed and executed, with attractive metal bodies / grille. Sound quality?Bose has the edge. Although their ostensible low-end frequency response is comparable, the Bose delivers much flatter, articulate bass right down to about 60Hz. You can easily defeat it - you'll hear sub-bass tones drop off, and at higher volumes the little bitty woofer and passive radiator just can't keep up with the mids and treble. I don't notice the bass fade at higher volumes on the B&O A1. But, at moderate listening levels, the Bose simply creates a more compelling delivery, surprising "oomph", warmth, "voice" at low tones. Additionally, perhaps due to the metal grille and somewhat unusual hockey-puck form factor, the B&O also does not reach the crisp highs as does the Bose - sparkling, precise treble well into the 15+KHz range. The B&O comes off a bit muffled, rounded off, maybe above the 8-10KHz range. I have docked the Bose half a notch for a very narrow sound stage, and to a degree, room placement; to get the most absolutely brilliant listening experience from the tiny thing, it is best situated 6 to 12 inches from a vertical corner, and you have to be almost directly in front of the unit. The treble is a bit "laser-like" in that respect - GOOD anywhere you stand, but mind-blowing when you're situated right within the soundstage. The B&O has a bit of oddness around treble as well. It's intended to be "360 degree" sound, and it is, but there are angles around the hockey puck that have a bit clearer treble than others.While the B&O clearly delivers good sound, and easily earns a long-in-coming, and hard-earned #3 slot in my ultra-portable stable, and is clearly the better of offerings from other esteemed names in the business (Bowers & Wilkins and KEF units named above), side by side, the Bose wins on sheer sound quality, and the A2 gives more kick, but at a larger size. I still would recommend buying this speaker if you want top-tier sound, in an extremely cool, swanky Scandinavian package. You would be doing very well in this category (littered with crummy product failures to deliver decent sound from a tiny package) with the Bose Soundlink Mini II, Soundlink Revolve+, B&O Beoplay A1 or B&O Beoplay A2. These are the only Very-good-to-great-sounding speakers I've tried to date. Among those, the Soundlink Mini still leads, but by a much narrower margin than before!