I'd say just get your feet wet, I'm a debian crosser myself, and I ran openSUSE for a while as well. Vector is a pretty sweet o/s. Its a little harder to get going but it well worth the effort. Plus if you have any questions the guys in the community do a great job answering them. I started running Vector about two weeks ago started with 5.9 RC1 then switched up to RC3 upon its release.
My only gripe with Slackware in general is software is an issue. That said, its just a matter of changing your prefered software or finding packages. if you can find them in a .tgz or .tlz format is as simple as right clicking and selecting Install. I have distro hopped for almost a year, and this is by far my favorite distro. Its a little frustrating, but the awesome community support, and once you get aquanted to how software is dealt with in slackware it's not a bad deal.
there's a built in program to convert rpm2tgz simply type that in the terminal and point it to an rpm it's worked for a few softwares.
I've used websites more then gslapt to get software being as slackware 12 is still kind of new and the repository's are a little dry.http://www.slacky.eu/
-italian site, I just use google language tools to translate the discriptionshttp://slackbuilds.org/
-its just slackbuild scripts, you download the script, and the source, then compile your own .tgz file for specific apps you want.
Its kind of fun I spent hours making packages to save on my server for myself and anyone that wants me to convert there box.http://www.linuxpackages.net/
I'm mentioning it as it was the first I tried out...its pretty lacking and a lot of the packages I grabbed off here didn't work, but for the sake of more options I'm mentioning it.
Again, I suggest you try it out, play with it, have fun. This is by far the best o/s I've seen offered up in the open source communities. One other thing I noticed, is in debian you have a tone of software available so your always looking for something better, or that more closely does what you need it to do. well using this o/s I've found even though the apps aren't my usual ones they do the job, they do it well and there stable.