Red Hat is probably the best and worse possible thing that can happen to CentOS, a community-based GNU/Linux distribution derived from it. The good part is you have the stability and good driver support since Red Hat is popular among the commercial world. The worst part is stability comes with a price. Getting latest greatest software updates (e.g. PHP or Subversion) is quite limited unless is a security fix. So you left with two choices, either you get the updates from third party repositories or you built from source code. Unfortunately, both ways have their own issues.
First, is always tricky to mix third party repositories and base repository. Certain common library packages maybe updated by third party repositories causing unnecessary breakage with existing software. Although Yum priority plugin and packages exclusion can solve that, it is still a hassle.
Second, installation by source code compilation. You can have all the customize options but with all the issues in former way as well. However, you can have the flexibility to isolate your installation into specific directory (/opt) with GNU Stow, a symlink farm manager. But you lost the ability to verify the integrity of your software binaries (check for tampering or planted Trojan) in case there is a security breach. To solve that, some may rebuild the software into RPM packages software from existing RPM's spec file which is what all the third party repositories are doing right now. In the end, you still back the problem of the first method.
How then ? Just migrate and move to a more bleeding edge distro like Ubuntu or Fedora.