Wow. Do you guys also like to exercise by jogging along the middle of the freeway at night? Wearing black clothes? Because there is no way in heck I'm going to install 10.5.1. right now. Why be a guinea pig? Wait until the bugs are worked out. I have a 4TB music collection I've collected and tagged extensively over 8 years, and no way, no how, am I going to risk it in even a small way by being an early adopter here. I'm on 10.4.1 and it's served me well. I'm sure it can continue to do so for another month or so, so why should I hurry in switching to 10.5.1. Heck, I'm still on Snow Leopard 10.6.8, and in no hurry to go to Lion. But I'll be happy to read about people's experiences of 10.5.1.
You're an outlier (I don't mean that in a bad way), and therefore your experience is of little interest to Apple or a vast majority of its users of iTunes. So it probably does not make a great deal sense for you to berate people about their jogging habits, etc.