I started Beta Testing Windows 10 (1-7-2015) and so far I am impressed. The issues that many users, including myself, did not like about Windows 8/8.1 have been resolved.
Windows 10 appears to be the best of both worlds, restoring many of the functions that Windows 7 users came to know and love and keeping some of the best features of Windows 8/8.1 which were very helpful for tablet users.
The testing period has a long ways to go, but so far, it looks promising. I deliberately chose run the test copy on an older laptop: 4 years old, 4 Gigs of Ram, AMD Processor. I was expecting a speed issue, but so far it is performing incredibly well.
Have tested with the following software and had no issues: Microsoft Office 365, Google Outlook Business Sync, Mozilla Firefox, Google Chrome, Adobe Reader and Flash. So far, so good.
Will keep updating this Blog as well Facebook as the testing phase takes place.