This may come as a surprise for you, but it is really hard to find any applications that are not bug-infested (be it commercial or free software). Of course exceptions exist for the areas where bugs can cost human life or introduce huge expenses.

It just happens that commercial vendors do not usually publish any information about their bugs for free access to everyone and put efforts into advertising their products as being high quality/superiour/best in the industry/etc. It is understandable as they want to make money and being completely honest does not pay off.

On the other hands, public bugtrackers of free software projects may contain a lot of bugreports, with quite a large share of them being duplicates, old unconfirmed bugs (somebody reported a single crash for example, but nobody could reproduce it later and the problem might be fixed long ago already), behaviour not expected by user but questionable if it is really a defect, very minor rarely encountered problems, etc. Really important and especially critical bugs are usually fixed quite fast. You can't directly judge quality only based on the number of issues registered in the bugtracker. Bugs are just not equal and a major bug may be a lot worse than a whole bunch of minor ones. Also popular and heavily used projects may have long error lists, with none of them being critical, while less popular projects may have lower quality with lower number of people caring to report bugs.