Yes, there you go, I said it. I've heard people at work talking about the virtues of Firefox's tabs compared to IE6, I've had people debate on forums over which extension for Firefox is best for adding addtional functionality to its tabs. Well I've been using IE7 for ages now, it has tabs, and for some reason they just don't do it for me.
For tabs (this is based on IE7, although a default Firefox install appears to be similar):
Less clutter on the taskbar
Quicker to flick between tabs
Opening something in a new tab will not automatically bring it into focus like Open in New Window will
You can already group similar taskbar buttons to avoid some of the clutter
The title of the current tab is shown, if you have multiple browser windows and multiple tabs it can get confusing to work out where you want to look, and can take time to flick between browser windows
Sometimes I'll close the browser when I really should have closed a tab, so I'll end up losing all the pages I was going to look at next, and having to use the history to bring them all back up
Reduces the amount of space on the screen
So there you have it. I think the main reason people talk about tabs is because it's one of the few obvious differences between Mozilla/Opera and IE. Once IE7 brings them in (bear in mind that the MSN Search Toolbar
lets you do them now, and NetCaptor
was first to bring in tabs - and is based on your installed IE engine), and its really good printing support, the only thing Mozilla fans can push is the extra functionality that you can have with tabs (or whatever else you want to fiddle with) thanks to 3rd party extensions - complete with their potential security risks and occasionally "best endeavours" support. I'd take better printing over better tabs anyday!