Define "Buggy"
My past history with 10.X upgrades has been very good. Yes, there were bugs fixed, security issues patched, other performance issues addressed, but none of them affected me. As someone already said, there will be bugs, but you run a pretty good chance that "performance issue in intel macs running 10.5 streaming itunes through remote computer library running 10.4" or some such problem won't affect your day to day computing experience. As a suggestion, I would say waiting will be fine if this is just a "day to day" home/some work computer (and it would save you$). If this is a mission critical machine, buy now. All current software applications have been through any growing pains of 10.4, and are potentially more stable than they will be on 10.5.