There is not much wrong with SAFARI (3.0) at least no more than it is with other browsers,
when experiencing the things you currently experience you should be highly alerted, and rather put your coding in question than the platform you are running against.
It is difficult to get code stable on all browsers and especially the webkit is a pain to work with.
Reduction of complexity and evolutionary programming is one(my) answer to SAFARI/OPERA etc.
I developed a quite complex framework(2112PowerWindows) and the first 4 weeks with SAFARI was like hell. So expect a learning curve here.