The reason you should care about IE 9 is because it's posting benchmarks that outperform all of Micrsosoft's competition -- including Chrome!
It's a game-changer because, if users don't bother to download the competition because they no longer see an IE bottleneck on their systems, Microsoft can recover some market share.
I recently installed IE9 RC and I have to say I'm a bit disappointed. I thought I'd give it a go after seeing the blurb on the new slim-line interface and being able to drag tabs to the Windows 7 task bar.
It's OK, but I've come across quite a few Web sites, including Facebook, that cause IE 9 to keep reloading the page. Also, I really miss the 'favourites' toolbar. Not sure why the write ups so far have all been so positive...I'd rather go back to IE8, to be honest, but don't want to mess my PC up.
I'll stick with it, but hopefully it'll get more stable with time.
'Microsoft is begging corporations to migrate IE 6-dependents apps to the far more standards-friendly and secure IE 9.'
Of course they are. At the risk of stating the obvious, IE 9 cannot be installed on user-friendly XP.
Also, in our case, we are staying with IE 7 because our legacy apps will not run on IE 8, let alone 9, and upgrading our legacy apps costs us a tiny bit more than MS is willing to provide.