if you dont mind tom i can break it down though you may already know some of this so im in no way insulting your IQ
distros=distributions
distributions are the different OS's
Gentoo, Suse, Overclockix, Fedora, elive
are all different distributions and are all different OS's
though ever distro is different the source code is usually very similar between them the source code like windows makes up the kernel.
the kernel is the core component to the OS
now though their are thousands of versions of linux their are only a few different kernels as these are open source they can be tweaked to build new versions of linux off of. which is why their are so many their are a few code bases (kernels) that are used the most.
these are
Debian
Knoppix
ubuntu
Gentoo
RPM
Fedora
Red hat
Slack ware
etc etc
all of which have their own version
for example with the gentoo code base their is a gentoo linux with the fedora code base Fedora etc...
also though linux can infact have a few glitches when first installed and if your new they seem to come at you even faster unlike wondows which is built to support multiple platforms linux while installing adjusts options and packages(software bundles) to fit your machine like a glove. That in itself makes it not as bloated or slow as you may think over the years with new ways of detection linux has become exremely fast. infact linux is used in over 500 of the worlds super computers.
that and unlike wondows which will need a reinstall if you screw up the system files if you manage to break linux you can DL a new kernel via update or command line to get your distro working tip top in no time
hope that helps.