I have had a Sonicare for more than 10 years now. We are on our 3rd brush (the 2nd one still works, handed down to the kids ;).
The best way I can sell you on it is this. Nobody in our family has ever had a cavity since we began using the Sonicare. I am good about flossing, but nobody else in the family is! So just on the Sonicare alone, I bet we've saved thousands of dollars in dentist bills (not to mention the pain and agony of having cavities, and having them filled!) My teeth cleanings usually last about 10 minutes - there's literally never any plaque or tartar to scrape off.
Costco sells the Sonicare for a good price. You may want to check it out if you are a Costco member.