Oddly enough, I have encountered very specific bugs in Safari. Not sure if others have seen any of the same ones.
I haven't encountered any of those. Instead I consistently run into two issues.
1) Due to unknown circumstances non-text form elements in Safari become extremely slow to process a change. For example, a select menu opens quickly, but hangs for as much as three seconds after a selection is made. Same goes for some other elements like check boxes or radio groups. Resolves, temporarily, when I restart the browser.
2) Safari eventually bogs down toward the point of becoming unusable. Lots of hangups while processing something or another, etc. Looks like some memory leaks but there seems to be something else to this as well. Granted, this is a fringe case, because by the time this happens I might have dozens of tabs open in a few windows, but I didn't have that problem in Snow Leopard. Also resolves, temporarily, when I restart the browser.
And there are a few relatively unimportant quirks. Web Inspector, when opened into the Console, cuts out a significant part of the overhead navigation buttons until I click the sliver of one showing and return to the console. Pretty annoying when debugging JavaScript. When I have a Web Inspector open for a page in the background sometimes it also litters the page with tooltips (similar to something I remember Windows XP doing when it slowed down and you dragged a window around, but at least that amused me).
Some links would be helpful. I do not think anybody has had any issues with Windows crashing or having any malware (except for the one they installed themselves) since Windows Vista. If only OS/X had such record. While Windows quality is increasing steadily OS/X has been in a downfall (quality wise) lately.
Search the web. Seriously. I was removing viruses from folks' Vista computers within weeks of official public adoption of the OS. Vista and Windows 7 are
far more secure than XP has become, but they still have numerous malware issues. Spend a few minutes reading malware removal boards if you really need some kind of confirmation.
And crashing? Vista crashed left and right when it first came out and it still doesn't run very smoothly. Windows 7 is much better, but I wouldn't consider it to be anywhere near as stable as a good OS X installation (there are many reasons for this, which mostly boil down to the multi-company collaboration that goes into a given Windows installation). Consumer versions of Windows have always been a little iffy in terms of stability, but Windows 7 finally represents the marriage of server and customer that was supposed to be a feature of Vista. Windows 2000 was, for example, about as stable as a person could want an OS to be.
In either case a great deal comes down to how much the user has bogged their system down with intrusive third-party software products.
