Is this for getting around London on the Tube?
Personally, I don't know what is better, but whenever I'm in London, I just use my normal debit (credit also probably works) card. Just tap, pay and get on the train. I though that they removed the requirement to have an oyster card a decade ago. Now, it is definitely possible to pay with card.
Does the oyster card actually have any benefits as opposed to just using a normal debit/credit card?
(I just didn't know that people have oyster cards now)