As reported by The Register here the ability to download the Windows 7 Release Candidate (RC) from the Microsoft site ends on the 15th August.
This is the first I’ve heard of this but apparently any beta installs (ie: non-RC version) will start to reboot every two hours starting the 1st July – this should be a pretty good incentive to move across to the RC version.
I’ve been running the Windows 7 beta (build 7000) x64 for the last 4 months and have found it to be stable, accommodate all my computer hardware and peripherals and perform really well, especially in comparison to Windows Vista.
The Windows 7 RC doesn’t expire until Q1 next year so you will get a good 6 months of use out of it before deciding to upgrade or not. Though I’m sure once you’ve started to use it you won’t want to revert back.
Downloads of the Windows 7 Release Candidate can be found on the Microsoft site here.