Glen Newton writes about a study done on bug-fixing speed and reliability for econometric software packages. Five proprietary packages were measured in 2004 with a common set of tests, those five packages and one open source package were measured again in 2010.
The study concludes that the open-source software has fewer known bugs at any given time (they are fixed shortly after being found) while more than half the proprietary software had many of the bugs discovered in 2004, still open in 2010. For example, after applying the basic set of tests to the open-source project, they found: “all of the errors were corrected within a week of our reporting.” But, after all those tests were applied to the proprietary projects in 2004, only two of the vendors had solved all of those problems by 2010.
They might have picked a model open-source project for this study, but still it shows what can happen if you pick a good open-source product.
Still, when you are choosing your suite of software, choose carefully (even if every candidate for your suite is free). Try to pick the lively, active projects (but not the ridiculously lively ones, that don’t bother to go back and fix their bugs at all).