OpenSuse was my first linux distro. I borrowed the install cd from my local vendor and It was pretty straight forward to install and I found it easier to use.I must say I loved it.Of all the RPM based distro's out there opensuse is the best, it has a good package manager called Zypper and has a lot of software packages in their repository and also great documentation.In my words I would always say better Opensuse than Ubuntu.
After using opensuse I began to read to what is linux and how it came into being and I read about Debian and how they elect their own leader and their policy towards stability moved me. My experience with debian is, it is a rock solid distro and you must have a death wish to break it. Once installed you can fine tune debian to your needs. As Dorothy in wizard of Oz would say " There is no place like home" I would say "there is no place like Debian". Even though many people say debian is suited only for servers, the truth is it is a good desktop distro as well. The goal of debian linux is to provide a stable os suited for production machines and to have a universal operating system for major computer architectures.Those who want stability rather than bleeding edge software that breaks your system, Debian is your best bet.
I Installed Slackware for a bit of a adventure and it certainly was an adventure. Slackware follows the simple policy: If it isn't broke don't try to fix it. It doesn't patch heavily that is why it's called Vanilla distribution.There is a saying if you learn redhat or debian you only learn that if you learn slackware you learn linux and remember people it is a golden word. It doesn't handle dependencies in installing software like apt-get. The user gets to install every other dependencies himself. Also you don't use binaries like deb or rpm; you use source tarballs to install the software you need. There are tools like slapt-get in Slackware they have limited software in repo it's better to use slack builds it's like manual installing in the process you learn what each software is and why they are needed. Let me give you a perspective, VLC isn't installed by default in slackware although there is AlienBob's binary slackware package for VLC (Yes there are binary slackware packages it ends with .tgz) I tried to compile from source using slackbuild it took me one and half hour to download all the packages and compile and installation took another three hours,by doing this I learned why each package is needed and also made judgement if a certain optional package is also needed or not. If it had been debian or suse or fedora enverything would have been handled by the package manager but by going through slackware's way one knows which package is installed why they are needed.Like Debian, Slackware is stable suited for both desktop and servers but somehow most people judge both Debian and Slackware are to be used only for servers but in reality it can also be used for desktop it's just people doesn't see it. People today see poison wrapped in shiny box and say they love it but medicine in a plain box they discard it even though it is good for one's health( it's midnight that's why I'm philosophic) that is what's going on in software world too. All i'm saying is that both Slackware and Debian doesn't get the recognition they deserve. Also I thank AlienBob a.k.a Eric Hameleers for providing binary packages for Slackware and tips for making life easier for every Slackware user out there.
P.S: The ranking I made in this list is certainly random.