I have definitely had more with Leopard than I ever had with Tiger, so I am really looking forward to this. I have been pushing Leopard hard, and finding that it is good, but not great.
But Leopard still kicks the teeth out of the XP Pro I am using at work, or the Windows 7 my boss is using. The kinds of problems we are having on those systems are just ridiculous. I have no idea how Microsoft manages to keep anyone on board.
I've never had a PC as crap and unreliable as my 2008 MacPro with Leopard being a remarkably buggy pice of cat poo. The beachball of doom is a regular occurence - many times a day, Finder randomly loses entire Hard drives for no reason, Cmd+Alt+ Esc gets more way more use than Cnt+Alt+Del ever did on the PC and today's very inconvienient annoyance is that I cannot use files on one of my HDs as I don't have the right permissions or something equally cretinous/obscure and difficult to fix. The workaround is to use my PC and open files on PC over network and alter them there. How dumb is that? Though thtat's a miracle in itself as Networking usually fails to work most of the time. I tried to alter files with my MBP over network, but couldn't change anything with that Mac either.
I also took my PC laptop with me on my recent travels and was very thankful as some things would simply not work with the MBP but worked no problem and with no installs needed on the PC - which saved my bacon a couple of times.
My Macs regularly go back to the Apple Store and don't get the issues resolved as the Geniuses cannot fix the issues or create new ones. My new MBP went back to store within 3 weeks, only to discover it was a Finder problem on all Macs. The problem - an invisible HD [and not for the first time], though only to Finder, all other software could see and use it, inc Disk Utility which set it up. But as Finder is how you open and save from within programmes, it's a bit crippling. If it wasn't for alternatives like Pathfinder to the abyssmal Loser, sorry Finder, I would simply not bother with OSX.
I'm hoping SL is a big improvement. I'm viewing it as a much needed service pack for leopard, as all the bugfixes so far seem to bring fresh issues. 10.5.7 has added a few new bugs like display issues
I've just installed W7 [RC] on the MBP and wil be interested to see if it's as good as everyone says.