Scoble just lost all his calendar events to a Mobile Me bug. He points out that:
Apple’s secrecy keeps them from properly testing out their apps with
tons of users, the way other companies do who aren’t so worried about
When people talk about open source software, they talk about the advantage of lots of testers. For example, Marten Mickos always talks about how he has two types of users with MySQL, those with lots of time and little money and those with lots of money and little time.
What I think doesn’t get enough attention is the fact that these "free users" aren’t your average user. They are usually very technical, very passionate, very active users. People that will help make sure you have the information to fix the problems they find. And if you label it a beta (as perhaps Apple should have done with Mobile Me), they know how to take appropriate precautions so that when terrible things happen, it doesn’t wipe out their data. Free and open source software developers can use and test your software in ways that the average user can’t or isn’t interested in doing.