I have been testing Windows 10 for more than 6 months now. I have published a page for it since March. I have updated it again for the new build.
Google has flooded that page so heavily that I had to upgrade my ISP plan several steps to cope with the deluge of page hits
The new 15.5 driver works a lot better with Windows 10, not nearly the problems that 15.4 presented. The new build also fixes a lot of graphics problems.
Both my HD 5450 and my HD 6970 are working well with Windows 10.