When it's searching for a Bluetooth device, you'll see a small light panel on the rear right side flashing. If you're not connected to the speaker you'll always have this small flashing light in action, which can be little distracting.
The 3.5mm aux-input overrides any Bluetooth connection when plugged in, and I've found that if you remove that input, the speaker quickly jumps back to any nearby device that was recently connected. If you get two GravaStars for a stereo experience, Bluetooth and TWS is ideal. Otherwise, using a single 3.5mm mini jack output, you'll need to get a channel splitter for left and right. Also, in this mode you'll need to manually adjust the volume for each speaker, at least to even the levels out.
The audio components include a 70mm (2.75-inch) full-range speaker from Harman Kardon on the front, with a bass diaphragm of polyphenylene composite and a metal magnetic core on the back. The Qualcomm chip runs the show, along with a TI 3118 amplifier to pump out 20W. For its relatively small 5.5-inch diameter, this speaker can pump out decent sound levels. As computer speakers, a little distance seems to improve the sound experience for me when they're cranked up, and angling them away from the center point (for example, your computer chair) seems preferable since it's a front-throw speaker only.
I don't have any similar front-facing Bluetooth speakers for lying around, but I did match it against the UE Megaboom 3 ($199), JBL Link 300 ($200) and the older UE Boom 2 ($100) for a comparison with existing products. These are mostly designed for 360-degree sound, so it's worth noting that the output isn't quite the same as the GravaStar. Essentially, both the JBL Link 300 and Megaboom 3 are bassier and a bit louder, with clearer representation of subtle sounds. They're also both physically larger, with the JBL running two 25W speakers and a larger bass diaphragm (although it's not portable). The UE Boom 2, however, falls short of the GravaStar's output.
Sadly, I couldn't properly test the TWS sound experience, since I only had one of the final models. I did somehow manage to get it paired with the earlier version that had a lesser components. As is often the case, two or more Bluetooth devices can really fill a room and offer a spatially immersive sound. The contrast in quality between the two was noticeable, though, which reinforces the company's decision to upgrade the internals.