As a speaker gets smaller, it also loses sound quality. So while the two inch tall Muse Mini is certainly the most compact Bluetooth speaker I've seen, I have my doubts it can really compare with larger alternatives like the foxLv2 or the Jambox.
Compared to the minuscule speaker on your smartphone I'm sure the 2.2 watt Muse Mini sounds like a dream, but I doubt the difference is as noticeable when paired with a larger device like a laptop. Its USB rechargeable battery is good for up to four hours of playtime when connected to an audio source over Bluetooth, but switching to the tethered line-in cable should gain you a few more hours of low-fidelity listening pleasure.
There is one advantage to sacrificing sound for size, though, and that's price. At $43 the Mini Muse is also one of the cheapest Bluetooth speakers you can buy. Even if the only way it can spice up a meal is with Salsa music. [Muse Mini via The Gadgeteer]