Below is a chart that compares the two Sonicare electric toothbrushes, the Sonicare Flexcare & the Sonicare Elite Premium. At the bottom you can click on the review button to see what others have to say.

Sonicare Flexcare
Sonicare Elite Premium
 Retail Price: $169.99  $149.99
 Modes of cleaning:  3 – clean, massage, & sensitive  2 – clean & massage
Includes:  Brush head, travel case, & charger  2 toothbrushes, 3 brush heads,
2 travel cases, 2 chargers
 Warranty:  2 year  2 year
 Built in timer:  2 different timers. 1-minute quick mode & 3-minute cleaning mode;
both with 30 second intervals
  30 second intervals for 2 minutes
 Battery type: Lithium ion Nickel–metal hydride
Rating: 4-half-star 4-half-star
sonicare-flexcare-reviews sonicare-elite-premium-reviews

As you can see they are very different electric toothbrushes. If you want more options as to the different types of cleaning modes and better battery than the Sonicare Flexcare is the one for you. If you are looking to get a little more value for your money, than the Sonicare Elite Premium is the one for you as it comes with additional brush heads which will save you the cost of replacement in the future. You can’t go wrong with either one and they are both excellent toothbrushes from Sonicare.