more for less
I previously owned a much more expensive model brush by the same company that I used for about 3 years before the non-replaceable battery died.  Happy with the basic product but not thrilled at the sort-of-short lifespan,  I opted to buy a less expensive model by the same company ($12 vs. about $50).  Guess what?  Except for the lack of a short 1-second pause in brushing action every 30 seconds to tell you to move on to the next brushing quadrant, I don't feel or see any difference.  The battery keeps a charge for at least 3 days of brushing so it's good for weekend trips (the charger is very small so extended trips are not an issue).  What a bargain at $12.00.  Rather than a throw-away quick fix, I am very pleased with this model highly recommend it.
Rating: 5 stars