I've noticed that, whenever older Macs are discussed, the topic of OS version comes up, and this inevitably leads to several users chiming in on downgrading to a previous version of OS X for better performance. I've even seen Panther recommended recently as the OS for a daily-use backup laptop, although most commonly it's a recommendation of Tiger over Leopard, and there never seems to be any consolidation of the matter. So my question is: why recommend a version of OS X that is having it's support phased out when the hardware in question is capable of more? To me, this is like suggesting that someone run Windows 98 on a 2002 era desktop because it might run faster than XP. While is may or may not run faster, the user is put at risk from a security perspective, and the user will have a harder and harder time finding hardware and software that accommodates their older OS. Leopard has some very advantageous security and safety features (randomization of memory addresses for system functions is one that comes to mind, the other is Time Machine, which on a system that could have a 4-6 year old hard drive in it, is a life saver). If it's not possible to run Leopard on your system (slower G4 or G3 systems for instance) then I can completely understand, but if the system can support it, I wouldn't hesitate to recommend it. Then again, even if it doesn't directly support it, it can work out well in the end. My iMac isn't technically supported under Leopard; I had to jury-rig the install process to get it on here. However, it has proven to be no slower than Tiger for the equivalent tasks. Not only that, but there are some software updates that have recently surfaced that I would not have been able to take advantage of had it not been for Leopard. Safari 5 is a good example. HTML5 support screams compared to Safari 4, which is the last version I'd be able to enjoy on a Tiger install. I now can enjoy internet video on an eight year old computer! My experience is just one experience, but if my system is relatively snappy, I have trouble following how a PowerBook with a processor almost 1Ghz ahead of my paltry 700Mhz, could be a lame duck under Leopard if given sufficient quantities of memory. Also, I suppose snappy is in the eye of the beholder. If you're looking for MacBook-equivalent speed, you won't find it on these machines no matter what you install on them. I just don't see how the extra speed can outweigh the cons of an older installation, if not Tiger, then certainly Panther and below. Thoughts welcome. I just noticed this comes up a lot, and it's fun to talk it out.