Vibrators
Charging, noise and waterproofing decide whether it gets used twice or gets used for years. Power is the least useful thing to compare.
The category splits three ways. Rechargeable vibrators that do one thing well, air-pulse devices that work on a completely different mechanism, and app-controlled models where the software matters as much as the motor. Most people only ever need the first. The other two are worth understanding because they solve problems the first one cannot, and because the reviews for all three get mixed together in ways that make them useless.
Related guides
The questions that come up before and after buying.
Is it actually waterproof?
IPX7 is a real standard and most listings quote it correctly. What it does not tell you is that the test is done in clean, still, cold water on a brand-new unit, which is not the situation you are buying it for.
How to actually clean one
Most cleaning advice for these products is either too vague to act on or quietly wrong about the materials. The part that matters is knowing which of two categories yours falls into, because the two need different things and one of them cannot be sterilised at all.