Source control considerations

Pros

 * 1) Most popular source control system.
 * 2) Mature and stable API with bindings for virtually every programming language.
 * 3) Simple.
 * 4) Lots of GUI clients.
 * 5) TortoiseSVN especially rocks.

Cons

 * 1) Requires a network connection for most operations.
 * 2) Due to the above, slow in many cases. Even worse, can be über-slow for blames on files with long history.
 * 3) Doesn't have some functuions DVCS users are used to, such as bisect or stash.
 * 4) Greater load on server.

Pros

 * 1) Fast.
 * 2) Surprisingly, has good GUI client for Windows.
 * 3) Lots of features, though sometimes even too many of them, making learning harder.

Cons

 * 1) Lots of annoying Git/Linux fanboys screaming "hell yeah!" but having no idea what the hell they're talking about.
 * 2) Has problems with cross-platformness. No native ports to Windows, users can use either Cygwin, which is a horrible monster, or Msysgit. The latter has no git-daemon, and both have problems with localised filenames (not a problem for current MediaWiki codebase, but still).
 * 3) Git-gui simply sucks. Those who disagree are advised to try using TortoiseSVN for a couple weeks, abstracting themselves from SVN deficiencies.
 * 4) Licensed under the over-restrictive GPL, which makes creation of bindings for different programming languages and IDE intergation problematic. Spawning a process and parsing its stdout really sucks if compared to an API.