The revision management system Bazaar (aka "bzr") is an occasionally flaky little thing and I've experienced several crashes doing mundane tasks. I much prefer using Git or even Subversion as they've proven to be rock solid in my use of them over the years.
Huge thanks to the msysgit team for their hard work, because after some testing I've discovered that their git/git-svn port does work, whereas trying to get it working under Cygwin is a quite broken right now. Got git it!
Note: You need to get the Git-1.5.5-preview20080413.exe release if you want to try git-svn, the Git-1.5.6.1-preview20080701.exe release has a broken git-svn.
While trying to get git-svn to work on cygwin I came across a bunch of problems. As it turns out there are some problems with subversion-perl that ultimately cause git-svn to fail. Unfortunately it could be another few weeks before this is fixed as the maintainer of that perl module is on vacation. Argh.