Meanwhile there are tons of pocket-sized portable speakers around. I haven't heard all of them, but the Wavemaster MOBI was one of the most popular ultraportable speakers and top-seller in Germany for a long time. You could also find it under different brands like "Cabstone Sounddisc", or "Divoom Pop" and many others.
Fact was that compared to many similar speakers like X-Mini, Raikko Nano etc, the MOBI managed the best balanced sound somehow. The sound was still far away from anything really serious, but it was better than all the rest. I still own my old MOBI, which was one of my very first really portable speakers that small.
There has been a revised Bluetooth version out for some time now called MOBI-2, which took the crown and is now best selling speaker system according to Amazon.de. I wanted to check how much different both sounded and if the new version was any better costing 1/3 more. I prepared a video which hopefully can show you some differences in sound as well as which one will play louder etc.
Although the new version has Bluetooth I recorded both with a wired connection to get exactly the same conditions and not to disadvantage one of them.
I am also expecting a sample of the Teufel BT Bamster to arrive soon and will try comparing it to my Soundlink Mini using the same track as above, so you will hear the difference in sound ;-)
Update: Have a look here, how this sounds on the BT Bamster and Soundlink Mini.