installation of Percona on Centos 5.9

i am still a bit confused.
i have been using this guide
I am having mysql ver 14.14 distrib 5.1.66
what version of percona should i install
yum --disableexcludes=main install Percona-SQL-server-SET-CORRECT-VERSION-HERE


Generally, you should always go with the latest version as many bugs will be fixed in that. um_repo.html um_repo.html