As someone who's been using Windows 8 since its Preview release, I admit that I am not finding Windows 10 to be as impressive as someone who might have skipped over 8 entirely. To me, Windows 10 feels like Windows 8, and in many cases looks like it, too. Of course there's the new Start Menu, but that's not something that stands-out to me as being that major (even though it is, given that most people consider it to be a "fix").
Nonetheless, regular use is sure to expose more enhancements (or tweaks), as will further Preview releases. With Windows 10's final build not set to ship until mid-2015, that gives Microsoft quite a bit of time to continue building on what it has; and it's important that it does: Windows 10 has to be a winner.
On the topic of subtle enhancements, a major one coming to Windows 10 has to do with its Windows Update mechanism. Before, both consumer releases of the OS and enterprise ones adhered to different update rules, but because the same version of Windows 10 will be released for both audiences, changes had to be made.
The result is three different rulesets for updating. Currently, any consumer release of Windows will fetch updates as soon as they're available, and the basic mode for Windows 10 will match that. For enterprise use, there will be an option that downloads only security updates. In business, it's obviously less-than-ideal to roll-out updated or new features that no one's expecting - at the very worst, those updates could even break software.
The third option is one that might appeal to those wanting to update, and have large environments at-the-ready. It will allow the IT staff to vary how the update will roll-out to the entire environment. It could be that a small group will get it first, so they'll in effect be acting as guinea pigs. If testing goes well there, then the updates could be rolled-out to everyone else. If something goes wrong, then the issue will have plagued just a small group of people, and a fix could be worked on before the update hits the rest of the machines.
Tying into beta testing, Ars Technica reports that the Windows Insider program, which allows anyone to test Windows 10 Preview, might not conclude after the OS' release. Instead, Microsoft is in all likeliness going to keep the program going, so that willing participates will be able to continue testing new features of the OS before those features roll-out to the general public. This constant beta testing is important, and Microsoft might as well take advantage of the audience it has that's willing to do that testing.
While OS updates are hardly an interesting thing, it's still nice to see that even Windows Update is going to be overhauled in Windows 10.