From the strategic part, we are able accepts payments from all over the world and be responsive to the seasonality of the business or new scenarios by updating our rules or options in no time internally.
From the customer side, it is very easy for agents to perform quick transactions so our customers are happy.
I have been using Adyen along with other payment providers on the last years and this is the only software in which i feel all requirements are met.
It is very easy to configure according to your business needs and supports all kinds of cards and payments (including real time bank transfer transactions or other payment methods not that common in US or Europe). You can easily configure the rules to accept or block a transaction (every rule set can be different for each merchant which is very useful when dealing with multiple markets and clients).
Status of a transaction are very easy to read and to perform full and partial refunds, answer chargebacks or just to consult a payment.
It is possible to download reports of the payments which contain good information for a good analysis.
Customer service is very responsive and always gave useful answers to my queries.
I don't really see many cons on Adyen, but if I have to pick an area in which I would like to see more development on the future, it would be for sure the fraud/risk part.