All payservers care about is getting as many people on their servers as possible to make money from genuine sharers cards they exchange with,it is not uncommon for them to have no local card and pass others off as their own.
They fast become over subscribed and you will not get a stable picture. Once they absolutely need to make space for new subscribers they will boot someone off even if they have paid.They will close a server and start another without warning,they are only there to make money and dont care about those who have paid.
They are the most likely to get busted, and your IP can be recovered from the server wether you pay or exchange with them. Guess who's door gets knocked on next ? Be very careful who you are sharing with.
Please do not support payservers they are killing our hobby.The real clue is in the name "cardSharing" - enough said