Buy the Aquasonic Black Series.

It does the daily job the iO does, for a fraction of the cost and hassle.

What was compared

Aquasonic Black Series Ultra Whitening Toothbrush – ADA Accepted Electric Toothbrush- 8 Br... — $27.99
Oral-B iO Series 3 Limited Deep Clean Rechargeable Electric Toothbrush for Adults, Black, ... — $299.99

1. 8 heads included beats 2, and cheaper refills
Aquasonic ships with 8 brush heads good for about 2.5 years, while the Oral-B iO Series 3 gives you just 2 and reviewers flag its replacement heads as expensive. Total cost of ownership isn't close here.
2. You're paying way more for the same daily result
The Aquasonic sits at a fraction of the Oral-B iO Series 3's price. One reviewer comparing the same iO line admitted it 'doesn't clean the teeth any better or worse' than a cheaper rival, which guts the case for paying so much more.
3. A charge that actually survives a trip
Aquasonic owners report roughly 4 weeks of use per charge. The higher-end Oral-B iO models are called out in research for battery longevity issues, which is a bad look for a toothbrush that costs this much.
4. Fewer build complaints, less daily annoyance
Reviewers flag the Oral-B iO's charging case as flimsy and prone to toppling over, plus mold buildup on parts. Aquasonic's simpler design and travel case avoid those specific complaints in the research.
5. Yes, the iO cleans a bit better. It doesn't matter here.
Oral-B markets clinically proven plaque removal along the gumline, and that's real. But Aquasonic is ADA accepted for plaque and gingivitis reduction too, so for normal daily brushing you're paying a huge premium for a gap most mouths won't notice.