According to the Direct2Dell blog, The DELL Test Centre team has been testing hundreds of Dell systems with  Windows 7 Release Candidate installed and they say that the results are promising. Here are a few noteworthy points from what the team has found out:

• On many systems noticeable improvements were seen in boot to desktop times for Windows 7 as compared to Windows Vista.
• Almost all existing Vista drivers are working well on Windows 7. This shows great sign in terms of compatibility.
• Vista Application compatibility with Windows 7 is promising as well (including the IE 8 compatibility mode)
• Transcoding (ripping) media files in Windows 7 is faster than that in Windows Vista .