To be honest, I've never heard a Bluetooth speaker I liked, because better sound was available from wired speakers, like the AktiMate Micro model. They're sold in pairs for $499, so you get true stereo sound, a rarity even with higher-end Bluetooth and most other wireless alternatives like the $600 Bowers & Wilkins Zeppelin Air, $600 Bose SoundDock 10, or $399 Sonos Play:5. Those three are perfectly fine for what they are, but wired stereo speakers from Audioengine, Emotiva, and AktiMate sound better, much closer to what I hear from traditional hi-fi speakers. True, they're not as easy to move from room to room as those wireless models, so if mobility is a higher priority than sound, pick up a wireless speaker.
The AktiMate Micros have a proprietary 4-inch Kevlar woofer and a 1-inch soft-dome tweeter. The back panels have a slot port. The desktop-friendly design measures a tidy 5.7x7.87x9.45 inches, and they are available in high-gloss red, white, or black.
The left speaker houses an in-house-designed stereo 40-watt Class D amp that powers both speakers, a stereo analog 3.5mm input and a USB input, and on the front baffle, an input selector and rotary volume control. The built-in DAC tops out at 16-bit/48KHz audio, and it's not bad, but you can easily do better with an inexpensive external DAC, like my $99 Schiit Modi. Then again, the Micro's internal DAC is about average for a desktop speaker -- none of them are standouts -- but the Micro's DAC will certainly clobber the sound available from your computer's analog jacks.
The top of the left speaker also has a flip-open panel that reveals a 30-pin docking connector compatible with most older-generation iPhones and iPods, but not the latest Apple devices with the Lightning connector. The right speaker is passive and just has a pair of all-metal binding posts on the back panel.
I played my iPod Classic, docked to the Micros, and was impressed by the speakers' clarity and resolution. Bass isn't as deep or full as from the Audioengine A5+ speakers, for comparison, but the Micros' low end is tauter and more precise. To maximize the speakers' bass output I put them near a wall, and that filled out the bottom a bit. The little guys play loud enough to fill a decent-size room.
I watched a few movies and was generally satisfied with the Micros' sound, but home theater bombast was in short supply. I don't see an easy way to add a subwoofer to the system, but the sound on straight dramas and comedies was very good. Dialogue was articulate and natural.
Comparing the Micros with my desktop reference Emotiva Airmotiv 4 speakers ($349/pair), the differences were readily apparent. The Airmotiv 4s make more bass, but the Micros were more dynamically alive. The Airmotiv 4s played louder and had superior treble extension, but the Micros were more open and had better soundstage depth. I like both speakers, but I'm sticking with my Emotivas.