you already bought it? cons are that it will blow up if you add water to it lol, seriously though, no battery last forever so it will eventually die which at that point it becomes yet another wall charger.
kinda asking for cons in reverse order...
1. you ask for pros and cons.
2. make decision to buy based on pros and cons.
3a. buy and enjoy your product.
3b. not buy, continue searching repeat 1-3 until product is found.
http://www.yogenstore.com/
I'm getting one of these! Portable all you need is elbow grease.
http://www.youtube.com/watch?v=eqUqcxVQ1TI