The major differences between IE7 RC1 and the previous beta releases are improved performance and the ability to install it automatically without the need to manually uninstall previous versions. There are also additional language options coming in September when a Spanish and French version will be available.

The new build apparently has improvements in performance, stability, security, and application compatibility. Support for CSS has been enhanced and everything is up&running. This is why Microsoft said that probably won’t be a RC2 version because this one is almost the final version.

Paul Thurrott says [1] in his blog that “I don’t think there’s enough there to sway Firefox users quite yet”.

Mozilla estimates that Firefox has more than 15% market share and the new version, [2] Firefox 2.0, will have a Beta 2 version released on August 30 and a final version will be available on October 24 with a RC1 version released on September 19.

We will see if Firefox will be able to keep the ascending trend. With a news like Microsoft [3] inviting Firefox development team to Redmond it is clear that even Microsoft understood that Firefox is a serious candidate and competitor for Internet Explorer 7.