Does it really help with arthritis?

Yes, that is its main selling point. You hold it on the rim and press a button; there is no squeezing or twisting, which is the part manual openers make hard.

Does it leave sharp edges?

It cuts the lid below the rim, so the can edge and the lid edge are smooth rather than sharp. You still lift the lid off with your fingers or a fork.

Does it need batteries or a charger?

Handheld models like this run on batteries, usually AA, so keep spares on hand. It is not a plug-in countertop opener.

Will it work on large or odd-shaped cans?

It handles standard round cans, including large soup and vegetable sizes. Very tall, square or badly dented cans can stop it from gripping the rim.

Can I put it in the dishwasher?

No. Wipe the cutting area and body with a damp cloth. Submerging it will ruin the motor and battery contacts.

How does it compare with a manual opener?

It is faster and much easier on the hands, but it costs more, needs batteries and takes up more drawer space. A manual opener never runs out of power.