Buy the Oral-B iO Series 3.

One of these is a dentist-grade tool with a decade of proof behind it, the other is a stranger's motor with 170 reviews and a shaky 3.9 stars.

What was compared

GRAUICI Deep Clean Rechargeable Electric Powered Toothbrush, Rechargeable Electric Toothbr... — $34.99
Oral-B iO Series 3 Limited Deep Clean Rechargeable Electric Toothbrush for Adults, Black, ... — $379.99

1. It actually strips more plaque, not just claims to
Oral-B's oscillating-rotating round head is clinically documented to remove far more plaque along the gumline than standard brushing. GRAUICI just lists RPM numbers with no independent testing behind them.
2. 18,943 people already vouch for it, GRAUICI has 170
Oral-B iO Series 3 sits at 4.3 stars across nearly 19,000 ratings, a sample size that actually means something. GRAUICI's 3.9 stars comes from just 170 buyers, too thin to trust with your teeth for years.
3. Built by a dental brand, not a random Amazon seller
Oral-B is the brand dentists actually hand out and recommend, with decades of motor and durability data behind it. GRAUICI is an unknown label with no track record, and cheap toothbrush motors are exactly where early failures show up.
4. Extra heads sound generous, they barely matter
GRAUICI throws in 8 heads against Oral-B's 2, but dentists say swap heads every 3 months, so that is roughly the same 2-year supply either way once you buy a couple of Oral-B refills. Unless you hate reordering heads, this is not a real advantage.
5. Yes it costs more. Buy it anyway.
The price gap here is real and steep, no dodging that. But a toothbrush you use twice a day for years is not where you gamble on an unproven $35 brand, and the proven plaque removal and gum protection are worth paying for if you actually care about your gums, which most people buying an electric toothbrush do.