Today I downloaded IE9 RC and also the new Adobe Flash Player 10.2 and found that the problems with Windows Live Writer 2011 now are fixed. After some initial tests I have not run into any issues and hope it stays that way. Update: see issues found at the bottom. Not as stable as I first hoped.
I can see that the performance in the IE9 RC has been improved further than earlier beta and IE9 is much quicker than IE8.
One nice addition I like in the RC is the ability to show tabs on a separate row . Just right click on a tab.
I like the ability to close a tab with one click without having to activate it first and also the ability to drag tabs to a separate Window or to snap them using Aero Snap.
Where is the RSS icon? You need to show the Command bar. Right-click on the empty space to the right of the New Tab button or other places on the top frame.
One small annoyance is that the colors used for groups are totally random and even though a group is created from the same page over and over again there is a new color each time. I had the third tab active and opened a new tab using Ctrl click on a link and got one color (see tab 3 and 4).
I then closed this new tab and did the same thing again and got another color (yellow).
The only way I found to avoid this is to disable tab groups completely. I wish the color choice was more consistent and in the example above that the color was the same. I can also imagine others wanting to decide what colors or color scheme to use.
After some further usage I do see some performance issues when quickly navigating sites. It still is not possible to click on say 5-10 links holding down Ctrl. There is also problem when Ctrl click to open a new tab and right after that trying to click on another tab that is open.
After some more usage I have run into IE9 RC hanging completely on a few pages (here is one sample if you want to try) that works fine in other Browsers and also crashing while searching for text on a page. Quite often I also find that there are iexplorer processes that are not closed and sometimes takes a lot of CPU having to kill them via Task Manager. This still apply to the RTM version 9.0.8112.16421.
Autodesk Discussion Groups need Compatibility View enabled to be able to post even with the released version of IE9.