I think first and foremost one of the sound that is nevertheless quite different: Wavemaster MOBI Mobile Speaker System black achieves a higher maximum volume and sounds much fuller. The X-mini II Capsule Speaker for MP3 players black, however missing the middle, so that the sound somewhat muffled fails.
I like the design better while X-mini II, it just looks valent, but the Wavemaster MOBI fit due to flat construction better in your pocket.
Conclusion: Due to the smooth sound I keep the Wavemaster MOBI. The disadvantage I find that both products no charger is included for the wall socket, but only a USB cable for charging from the PC / Notebook.
The video is unedited and should reflect my perception, but shows a little too much treble, which is due to the camera's microphone.