The main benefit for me is that it provides a very stable user experience since it is not under the influence of the war between linux distros; you learn the system once and you might spend 5 minutes after a major update learning what is new and configuring. But much of that software in ports is developed for linux with no consideration for BSD so it can cause headaches since the maintainers of those ports can not possibly test every possible use case and generally port it for their own case. A big rub for me is the sound situation, I love OSS but not all programs support it so I still get stuck using Jack.
I almost made the switch to FreeBSD a few times but Slackware still offers fewer compromises for me with the same ridiculously stable user experience and I don't have to worry as much about drivers when computer shopping. I assume I will end up switching to FreeBSD when Patrick dies since Slackware will probably die with him so I keep an eye on it and play with it once every year or two.
I almost made the switch to FreeBSD a few times but Slackware still offers fewer compromises for me with the same ridiculously stable user experience and I don't have to worry as much about drivers when computer shopping. I assume I will end up switching to FreeBSD when Patrick dies since Slackware will probably die with him so I keep an eye on it and play with it once every year or two.