Gentoo the slick penguin
I actually don't use a distribution, it's called a "meta-distribution" (*wiseasses*)
I'm using Gentoo for several reasons. Gentoo can be seen as a comfortable version of LFS (Linux from scratch) for lazy people.
Gentoo allows me to absolutely individualize a lot of things without having to do alle the work neccessary when building LFS. You can have it fancy shiny with flashing lights or spartanic, simple and not being a resource hog. It's also quite fast and furthermore it supports a broad variety of architectures. I guess it probrbly competes in that point with NetBSD. At home I yet(!) only use various x86 and amd64 but it would allow me also to use it on ppc, sparc, arm and many others. Okay, not all with full package tree but of course it won't make sense to run openoffice or similar on embedded-style chips.
Another important poit for me was the learning. The curve is steep and I still have to read a lot of things and research stuff. But I'm in science anyway and I WANT to understand Linux, at least to a certain degree.
Yes and no.
If you are willing and able to put a lot of effort in it, read manpages, books, forums and if you want to learn, understand and of course want all the individualism then Gentoo or LFS are right for you.
If you just want to work and have all the issues to a distributot, well, then you're probably better off with a precompiled one like the many Debian derivates, RH derivates, Mandriva or SuSE or whatever you like.
By doing gentoo I realized what a horrible lot of work distributors have to do. All the patching, localization (still a horror for me on the console and xorg-server 1.5.x, KDE on older xorg works out of the box), messing around in config files (*1), and just glueing all the libs and progs together ... it's like building a house. Either you take the bricks and put concrete between them, build in metal to stabilize and so on, or you just buy a finished ready-to-move-in apartement. LFS people even have to forge their bricks out of raw stone, Gentoo people can skip at least that one.
But if your Gentoo distribution is set up once then you just have to do the updates and as long as they are minor it's easy and always up to date. Note: Gentoo has no versions. There is no such Gentoo 9.04 or whatever, every daily portage snapshot is kind of a new version. So it's constantly in a flow.
You also can install Gentoo on any computer with a network connection. You don't actually need the Gentoo install media, though it provides you with everything neccessary. What you need is net access, fdisk style prog and some mkfs that is able to create any Linux suitable FS and a kernel that can access your mass storage (only a problem with really recent storage controller chips).
+ individuality at max
+ speed possible
+ always up to date (if package maintainers don't sleep and forget to update tree...)
+ lots of learning and understanding
+ no versions (I see that as a pro, there is no problems with having e.g. LTS or not)
+ can be installed from any OS that has a network connection
+ available for many many HW platforms
+ prolly things I forgot
- you better have a flatrate and also a fast net connection
- a quick CPU is helpful for compiling (e.g. AMD 4850e is already very fine, a VIA C3-2 well... it's still bearable but takes very noticeably longer, slower than older Duron/Celeron class you better cross compile large packages)
- lots of work, at least at the beginning
- you can't just put in CD, install in about 15 minutes, reboot and start to work
- prolly things I forgot
(*1) well, okay, probably most users on any distribution have seen at least their xorg.conf and messed around with it. I think it sucks but the new hal driven stuff stinks, too.
Stop TCPA, stupid software patents and corrupt politicians!