I must say that my IE 9 looks pretty much like IE 8 did. I know I tweaked a few things on the RC which seem to have carried through to the RTM - I've forgotten exactly what. But it's much faster than 8 was. I've tried all the other browsers but there's not really a lot of difference in the end.
of top of my head.
tabs use different theme to IE8, they take on the windows 7 theme instead of IE theme colouring, as it so happens my windows 7 theme makes ie9 tabs look horrid as the text is barely readable.
by default status bar amongst other things is disabled and tabs share a bar with menu. This can be fixed by changing various settings however the status bar is largely redundant when enabled, it seems to be cosmetic only in IE9 and non functional. The toolbar layout cannot be tuned from when I tried to exactly how was in IE8.
Cleartype (as mentioned by andrue) is forcefully turned on, making various sites look unusual to what I am used to.
There is other things but I cannot remember of the top of my head now, the status bar is more than cosmetic for me as I use simple adblock addon which as no menu configuration at all, it relies on the user clicking the icon on the status bar, the problem in IE9 this icon doesnt appear due to the redundant status bar configuration. I also cant get my head around of not having a progress bar during page loads.
For me to adopt IE9 it seems a few things need to happen.
simple adblock to be updated to work within it better.
someone to come up with a solution to get a functional status bar again in terms of the privacy icon (which I use to check blocked cookies and to add cookie overides) and progress bar on page loads.
a theme fix to fix the tab issue, that would probably be me doing something to my theme to make it work with IE9.
There is also the button layout changes. Maybe you just simply more able than to me to adopt to gui changes, in windows 7 I am the type of person who has heavily changed their gui to be more old school eg. bringing back quick launch and using a 3rd party app to change how the taskbar works so its more old school as well.
Microsoft appear to have this motto on everything they do. In office they did the same, ribbon forced on to the user with no options to have the old looks, lack of user choice, xbox360 with the new dashboard again has forced interface changes and colours that cannot be tuned. They seem to like to force gui updates on to end users.