Ratings and Reviews : Listing
My review is quite biased (I'm a dev for Source Mage). However, I will try to keep this as objective as possible, and I warmly invite anyone else to try out the distribution and contribute their own review, whether it agrees with my own or not.
I have run various distributions for reasonably lengthy periods of time (at least one year or more for each I have tried). The distro I used right before Source Mage was Gentoo. I have nothing against gentoo itself - it's great for what it is. However, I felt that it was either not meeting what I interpreted it's design goals and philosophy to be, or was moving away from that over time (I started using gentoo around 2003 or so, and switched to Source Mage in 2006). Additionally, I think that gentoo and I didn't match perfectly to begin with. You may consider me to be somewhat meticulous and a bit of a control freak. At any rate, I was looking to do things that gentoo either didn't enable me to do, or things that were not easy to implement in gentoo.
Then came Source Mage. I read the introductory documentation on it, and immediately became excited. It looked very promising that I would be able to compile any programs I wanted on my system with any options I wanted, and have all of that tracked by the package manager. This was the kind of flexibility I was looking for. The installation medium was not as polished as it could have been (in particular, at the time the latest release was 0.9.5, which lacked any kind of support for LVM, so I had to install via chroot from inside of gentoo). However, I got past that, and the install is pretty much a one-time thing anyway. After that, it fufilled my expectations. I could "cast spells" (in Source Mage parlance) in quite the way that was demonstrated in the documentation - arbitrary compile options were not only accepted, but tracked and MAINTAINED across upgrades, on a per-spell basis. This is Source Mage's greatest strength, in my opinion. It means you get exactly what you want on your system. No more extra dependencies or software bloat. But you won't get a 'crippled' system either that is missing the features you need/want. Coming in a very close second, however, is the Source Mage user and developer community - one of the warmest bunch of people I have stumbled across. Many of us will go to great lengths to help a user (or even dev) go from a complete newbie on a subject to an expert, coaching them along the way.
From what I have seen, the package manager is also one of Source Mage's weaknesses. Because you get per-spell customization, it means you have to go through the rigamarole of answering a bunch of questions to every spell, even if it is the same question you have answered for other spells. The problem is alleviated from the fact that sorcery remembers what dependencies and options you have said yes/no to, but the questions are still there (even if they just pass on with your default values). This is where gentoo wins out with its use flags. In other words, setting up a Source Mage system from scratch to a fully-loaded desktop environment is a time-consuming process, and requires work.
Whether the setup for Source Mage is really a weakness depends a lot on who you are though. If you are an anal, meticulous, and control-freaky sys-admin like I am, then you will love Source Mage (by the way, we also strictly adhere to upstream, so things are guaranteed to work as expected, at least according to upstream). If you are looking for a system that "does things for you", then perhaps Source Mage is not for you. It is also a lot more demanding on users for knowledge of how linux systems work. But if you don't yet know, you can learn it through Source Mage (and our community will be happy to help). However, if you don't really know how things work, more likely than not your beginning experiences with Source Mage will be frustrating (don't give up though! Stick with it and you might really enjoy it ;-D).
Also, the installation medium is improving. The current stable release is rotting a bit from age, but we are getting closer to a new stable release. Additionally, the interface will be much more robust and support many more features. If you need any help or have any suggestions for the installation media, there are plenty of us willing to lend an ear/helping hand (especially me, as I'm a dev for the install media :-D). Give Source Mage a try. If you don't like it, get rid of it, but please tell us why first ;-).