Artashes, PaySystems is not a merchant account. They are simply a lowly 3rd Party merchant account unfortunately.

WorldPay is not a true merchant account either, unfortunately, however are closer to one than PaySystems or 2CheckOut. However, according to lots, one of the best 3rd Party merchant accounts out there - and I think it is since it is backed by The Royal Bank of Scotland; and you can never go wrong with a bank.

If you are in Europe, you'll find it hard to find a true Merchant Account since there are not that many in Europe - it's best to go to your bank for that sort of information. Although, however in America there are lots of good ones - one being Authorize.net, also try ModernAuthorize and even CDGCommerce is quite good.

However, you may simply want to go with WorldPay - They are very good according to lots of people. Also, for the United Kingdom you may want to contact FastPay.co.uk, they are backed by NatWest and are like WorldPay - and have VERY good fees. 3% and £0.10, and personally I couldn't find better elsewhere and I'm sure you'll be hard pressed to find better for the United Kingdom as well.

Hope this helps.