(checked 2026-10-10)Based on 1,192 ratings for the HX9903/45 listing (12% 1-star, 2% 2-star).
Sonicare's app-connected premium brush cleans well and has a pressure sensor and a glass charging cup. It costs four times as much as the 4100, its heads are pricey, and 14% of Amazon ratings are 1-2 stars, mostly citing breakage and charging.
Top complaints
- Breaks or stops charging
Amazon's summary says durability and battery feedback are mixed: some units last up to 10 years but others break within months, and some don't charge at all. 12% of ratings are 1-star.
- High price and pricey heads
Electric Teeth lists the high price as a con. It found DiamondClean heads at $30 for a 2-pack or $50 for a 4-pack. Amazon's summary says some owners call it a bad investment.
- Noise
Amazon's summary says some customers find the noise too loud to tolerate for long. Electric Teeth measured 71 dB but still found it quieter than Oral-B models.
- No charging travel case, slow charge, one user per handle
Electric Teeth says the 9300, unlike the 9500 and 9700, can't charge inside its travel case. A full charge takes at least 24 hours, and the handle logs data for only one user.
What owners love
- Top-tier clean
Amazon shoppers praise its cleaning and whitening. Wirecutter found it gives nearly the same experience as Sonicare's $400 9900 Prestige.
- Pressure sensor, gentler than Oral-B
Wirecutter notes the lighted pressure sensor. Electric Teeth says the sensor slows the motor and finds Sonicare's clean gentler than Oral-B's.
- Long battery
Electric Teeth expects 14-25 days in normal use; its DiamondClean Smart test unit lasted about 25 days on high.
- You won't use the app
- You want to charge in the travel case (the 9300 can't)
- You're sensitive to brush noise
- Sonicare fans who want app coaching
- People who want a premium look and charging glass
- Customizing brushing with multiple modes and heads
Scores (tap for why)
What experts say
- Wirecutter (NYT): Mentioned among smart brushes: lighted pressure sensor, a lovely charging cup, and nearly the same experience as the $400 9900 Prestige. Wirecutter warns smart-brush apps tend to be buggy.
- Electric Teeth: 5/5 for the DiamondClean Smart line (tested on the 9500). The cons are a high price and no phone stand, and the 9300 lacks the charging travel case, making the 9500 worth the extra spend.