Cost:
One of the things that bothered me about the Sonicare was the high price of replacement heads and, at times, difficulty in finding a replacement head at all. The Oral-B 7850 doesn't have this problem. The replacement heads, while still more than a regular tooth brush, are far cheaper than Sonicare's. The cost of the brush itself, depending on where you purchase it, is also far less expensive.

Operation:
Both Sonicare and Oral-B have the same principle of 30 seconds per quadrant of your mouth to make a total of 2 minutes brushing. As others have noted, the drawback here is the lack of an automatic shut-off on the Oral-B.

In terms of cleanliness, the base of the Sonicare rests inside its recharger where old tooth paste and general muck tend to accumulate. The Oral-B, however, rests on top of a rod. Since there's no depression there's far less mess and what there is you see and can immediately clean up.

Effectiveness:
Consumer Reports has ranked Oral-B as being the best electronic tooth brush. It seems that other researchers have confirmed that conclusion. The smaller head of the Oral-B is far more effective at getting at hard to reach areas. After just a few days use it seems to me that it is indeed better at cleaning.

Overall:
Sonicare is a good brush. But in just a few days use I can safely say that the Oral-B is better. It's cheaper and more effective. About the only drawback I've seen is that it feels less solid than the Sonicare. It just feels like it might break more easily. But for now my brush is working great. I absolutely recommend it.

Pros and Cons of a Great Brush (Rating: 5.00)
Review : First off, I must say this is the best electronic brush I have used to date. Having tried some of the lesser-priced models out there...none of them thrilling me, I went ahead and splurged on this one. I bought the stripped-down version (brush only, no extras) at Target for $50 a couple of months ago.

Pros:
1. It is powerful. You will feel instantly comforted that you didn't just purchase a gimmick. If the high setting is too much for you, mashing the button will take you to a lower speed.

2. It is ergonomically sound. The shape and grip of this brush make brushing easy, and it can get to far back teeth quite well.
3. It looks nice and has a small footprint on your countertop - if that means anything to you.
4. The brush will not overcharge, unlike many rechargeable electronics, which allows you to keep it fully charged all the times without worrying about killing your battery life. And that is important considering that the battery cannot be replaced.
5. Oral-B/Braun guarantees that you will be satisfied with the results of this brush, and if you're not - even after 2 years of use - they will give you a full refund. That's what the manual says at least.
6. Built-in timer gives you an idea of how long you've been brushing. Dentists recommend at least two minutes
7. You're teeth will feel great, and your gums will surely be more healthy if you use this properly. Remember to brush your gums as much as your teeth...this will stimulate blood flow, and will also help rid bacteria from under the gum line.
8. Whitens naturally - over time. I quit smoking about four months ago, and since then my oral-b has helped remove stubborn tobacco stains from the backs of my front teeth.
9. Cleans in between teeth better than a normal toothbrush, but should not be considered a substitute to flossing.

Cons
1. I guess some people will consider this unit and the accompanying brush heads expensive, but you should put it in prospective...over time you will need less cleaning/scraping/drilling/surgery at the dentist/oral surgeon, and will have better overall oral health. That's it!

Advise: Do not use abrasive whitening toothpastes with this brush. The brush is powerful enough to whiten "naturally", and abrasive toothpastes may damage your teeth.

Say Goodbye to Ordinary Brushing!!! (Rating: 5.00)
Review : If you are like me, then you have just returned from the dentist and have vowed to take better care of your teeth.
This toothbrush is a great buy!

Pros:
1. Teeth feel cleaner compared to brushing with a regular toothbrush. I will never go back to regular toothbrushing again. It's just more convenient and most of us are probably brushing incorrectly anyway.
2. small brush head to reach the "hard to reach" places, like the molars.
3. easy to use.
4. replacement brush heads are relatively inexpensive.
5. price for the unit is not too bad.
6. big difference in performance as compared to the $15 base oral b electronic toothbrush i use to own.
7. 2 speed option just in case. (i dont really care for this feature).
8. great for taking care of the gums. I use to focus more on brushing my teeth, but with this toothbrush it helps take care of the gum line too.

Cons:
1. the toothbrush heads can be detached and stored but the problem is that after a couple of days it gets dirty in the storage area. just be sure to clean that area out frequently as you do not want to keep use a toothbrush that has a bunch of bacteria on it.
2. while the small brush heads make it convenient to reach harder places, you have to keep in mind that there is less surface area for the brush head so you literally have to brush tooth by tooth which takes a longer.
3. brushing can get a bit messy.
4. no auto shut-off feature (discussed below).
5. not as satisfied when trying to clean my tongue and below the tongue. (could be because of the small brush head)

Compared with Sonicare 7500.
1. price- oral b has price going for it.
2. reliability- this is arguable but i have never had any problems whatsoever with previous oral b products. While reading the reviews of the sonicare models I came across some reviews that indicated problems here and there. (i just didnt want to deal with that type of problem.)
3. RPM - the oral b model spins at approx. 40,000 rpm vs 31,000 rpm for the sonicare. i really dont know how much a factor the difference in speed helps but i assume that faster is better (?).
4. both the oral b and the sonicare models feature oscillating heads. (although not noted on the oral b description). (again, i dont know how much it helps having an oscillating feature).
5. No auto shut off feature- The Oral B does not have this feature, while the sonicare does. The reason why i believe this is an important feature is because at 40,000 rpm's you don't know exactly how much pressure is ok to use with the Oral B. At least with the sonicare, if you are using too much pressure, it shuts off automatically. Incorrect brushing can cause excessive wear and tear on portions of the teeth- such as with the enamel. Especially with the rise in use of whitening toothpastes that have more granules and such, you can do damage to the outer layer of the teeth. just keep in mind that you do not want to use too much pressure while brushing.
6. curiosity- being that we always want things that we dont have, i am curious as to how the sonicare performs.

Conclusion: great buy, and i am now a believer of electronic toothbrushes. i have tried regular brushing and it just doesnt feel the same anymore. dont expect this toothbrush to do miracles because in the end its a toothbrush. Even so, it performs as promised and my next dentist appointment will hopefully confirm that the health of my teeth and gums have improved. Price is reasonable and i do not foresee any issues with reliability.

Best investment in tooth care (Rating: 5.00)
Review : I feared my dentist. I was sure she enjoyed using the drill on my tender gums and teeth. Then she recommended sonicare. However, I found that sonicare with its large brush head was best for people with big mouth. Oral B on the other hand had round smaller head that was easy to use on the my molars. The brush itself cleaned effectively and quickly. It has been almost an year and my dentist struggles to find plaque and tartar on my teeth.

Not as good Sonicare (Rating: 3.00)
Review : I've got this one and the old Sonicare toothbrush. I bought this one as a replacement for my Sonicare, whose juice has just about run out.

Pros: smaller head, cheaper heads, interdental head, cheaper toothbrush
Cons: not as clean feeling as old Sonicare, battery life is worse, head life is shorter, no quadpacer

The two-speed thing feels useless because the lower speed feels harsher. The spinning brush doesn't do a better job either. Basically, you get what you pay for. Sonicare costs more and is better.