Small and Rechargeable
The size and the fact that it is rechargeable make it perfect for travel.  Unless you are travelling for a long time you won't need to take the charger because it holds a charge for a decent amount of time.  I use it everyday because, without cords, it is easy to use in the shower.  It would be 5 stars if the "soft" setting were a little softer.
Rating: 4 stars