I've been using an electric toothbrush for many years and I'm not talking about the drugstore cheapo versions (although I've tried those as well). I typically go for top of the line in almost anything I buy because I really believe you get what you pay for. With some things you can cut corners, but when it comes to my health or my teeth, that's not the time to make the cut. The most I've spent on an electric toothbrush in the past was around $180 for the Sonicare Diamondclean. It lasted me for many years, so if you break down the price over years, it wasn't all that expensive on an annual basis. Besides, we have spent that much going out to dinner at a really nice restaurant (that's how I typically justify the price of more "costly" items)! The Sonicare recently started acting up with it's brushing performance and the power button was getting hard to press, so I decided to replace it. I was satisfied with it's performance over the years, but wanted to try a round brush head this time and Oral B is the leader in that category. There are so many options with Oral B so I had to do a lot of research, starting at the top, of course. I was skeptical about the hefty price tag for the IO9, so I didn't immediately opt for the best of the best. I read many reviews and watched several videos for the IO, Genius, and Pro lines before finally deciding to just bite the bullet and go for it! The main feature I wanted with the IO9 that the others don't have is the 3D AI tracking. I have been getting really lazy with my brushing - walking around the house doing other things and really not paying attention to how effectively or how long I was brushing each area of my mouth. Yes, my Sonicare had a quadrant timer, but it didn't track how much time and effort was spent on all the zones. The IO9 tracks every surface of your teeth - inside, outside, chewing, left, right, front center and front bottom. It gives you a visual display on your phone as you're brushing so you know exactly when to move to the next area. It is taking me a little longer than normal - around 3 minutes (including tongue) to effectively brush everywhere, but that's okay, it's what I needed. I read some reviews and watched some videos that said the brush couldn't determine where it was in your mouth and I have not found that to be the case. My guess is that it partially learns your brushing habits to improve the tracking. I always brush in the same order, left to right, top to bottom, so it hasn't had any issues with accurately determining where the brush is in my mouth. I also like the pressure sensor that turns red when you're brushing too hard or your chosen color when not brushing hard enough. I didn't realize I was brushing harder than I should until I bought this toothbrush. The tongue cleaning mode is also useful as it's set for 30 seconds. I wasn't brushing nearly 30 seconds before this toothbrush. In summary, this is the best toothbrush I've ever used. Here are the pros and cons in my opinion: Pros: - Excellent, powerful cleaning backed by ADA approval - 3D tracking of all tooth surfaces with the app for a thorough clean - Tongue cleaning mode with set time - Larger brush head covers more area - Quiet - Fast charging - Sleek and attractive appearance and small footprint - Magnetic base that charges fast Cons: - Price - The brush head is a little large. I have a smaller mouth and it fits, but some might find it a little uncomfortable - My biggest gripe is that two people can't use the app unless you either use the same cell phone or constantly pair and unpair the base with each of your phones - The travel case only holds one brush and it doesn't use a USB charger like every other travel device