Honestly I'd stay on your Tiger until Apple sort these problems unless there is a reason to upgrade like a new bit of software that only runs on Leopard and you desperately need it.
Whilst Leopard seems fairly stable and a little faster (especially on the MBP) for the most part I'm still seeing all the issues I described in my posts and having way more apps crash or hang, in fact this rarely happened on Tiger.
If you are really worried then don't install it and if haven't opened the Leopard package then see if you can get you money back or sell it on until Apple sort out these pathetic bugs such as the Choppy Fullscreen Quicktime playback on screen resolutions higher than 1920x1080 on 30" displays, there are many people (check the Apple forums) on PPC & Intel Mac experiencing this so its not just me...
...quite frankly bugs like that are simply Microsoft and not what I had come to expect from Apple.
So far nothing especially serious just damn annoying, so its really up to your level of daring!
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