I hope you don't think I or the others were saying that the problems with the install were yours or any one else that had problems upgrading to Leopard. The issue mentioned in this blog is that he lost data because of the install problems, and that most definitely is his issue as he should have prepared before upgrading by backing up. The issues with the install is Apple's most definitely and I feel for you. I have bought Leopard myself, but I have not yet installed it as I want to make sure I backup up my system first and I also want to see how some of this transpires as well. Good luck and I hope the Genuises at the Bar can help. I'm sure they can.
An OS upgrade whether Apple or MS is a major upgrade and I think it is always wise to perform a backup or a Disk Clone just in case especially when you have important data to lose. You never know what might happen. I'm sorry but I think this is a trivial complaint as your friend should have done the backup first instead of wanting to be using the latest and greatest in such a hurry.