Both of these libraries are very good and great for your card game.
Pyro may be easier to learn and use, but Twisted will scale better if you ever want to move to a very large number of players.
Twisted can be difficult at first, but there are some books that will help you overcome the hump.
Some of the other libraries are selected, but you find that they are mature and widely used in the Python community, so you will have a better chance of finding answers to any questions.
My personal recommendation would be to use Pyro if you just want to play online, but go with Twisted if you have grandiose plans for a large number of players on the Internet.