Is it stable to use epel and rpmforge in the same time?

I use epel and rpmforge in my centos. But I recommend you to install the yum-priorities plugin since there are some programs in both repositories.

Ok, so here is the link of yum-priorities explained in detail: http://wiki.centos.org/PackageManagement/Yum/Priorities

But basically, after installing yum-priorities, you must edit /etc/yum/pluginconf.d/priorities.conf from enabled=0 to enabled=1

And also add this line to every repository (because there may be more than one) in every repo file in /eyc/yum.repos.d/

priority=Number

There is also a oneliner to see your priorities:

sed -n -e "/^\[/h; /priority *=/{ G; s/\n/ /; s/ity=/ity = /; p }" /etc/yum.repos.d/*.repo | sort -k3n

This is me output:

priority = 1 [base]
priority = 1 [centosplus]
priority = 1 [extras]
priority = 1 [updates]
priority = 2 [contrib]
priority = 10 [atrpms]
priority = 10 [elrepo]
priority = 10 [elrepo-extras]
priority = 10 [elrepo-kernel]
priority = 10 [epel]
priority = 10 [epel-debuginfo]
priority = 10 [epel-source]
priority = 11 [elrepo-testing]
priority = 11 [epel-testing]
priority = 11 [epel-testing-debuginfo]
priority = 11 [epel-testing-source]
priority = 20 [rpmforge]
priority = 20 [rpmforge-extras]
priority = 21 [rpmforge-testing]
priority = 30 [nfb] This is my own repo.