Community Support

When you use a ports system, your installation experience is shared with a vastly greater number of other users than if you had used a custom installation method for a particular program. This makes it much more likely that other users on a forum will be able to help in the event that you run into trouble. The boundaries set by the ports system make it much easier for other users on a forum to understand the problem, since they can be relatively sure that you haven't done something off-the-wall in your attempt to install a port. If there's a problem, odds are that it's a flaw in the port itself, which can be more easily identified than mistakes you've made (and probably haven't documented) in the installation process.

When there is a problem with a port, it's very unlikely that you'll ever be the first to encounter it, so odds are the answer is already out there waiting to be Googled.