Open source is not a cure against bugs. Open source is a cure against inability to fix them. You still need to fix the bugs you find, it's just vastly easier than in case of close-source. If you find a bug, you can take things in your hands and fix it, instead of having to get used to it and find workarounds, or hope for upgrade. The quality of the code wildly varies in both cases (some Open Source is written by total amateurs without QA whatsoever, some is written by pros doing this for prestige and idea. In proprietary, some programmers write bad code because it's less effort and the manager won't ever notice, some write good because they are afraid they would get fired) but maintainablity from the user point of view is much higher in Open Source. It's not a silver bullet, it just helps some. And because there's no customers/money to lose, people are less ashamed to talk about their mistakes and problems.