Most of the posts dissing Win10 are written by people jumping on the hate wagon which have none or very limited background in IT. In terms of engineering Win10 is the most advanced so far under the hood and very performance oriented. In terms of security it has far less exploitable systems and it forces updates on users (which btw is a good thing, as i seen lots of systems with updates turned off for really mind boggling reasons) so that everyone uses the latest fixes and creates less version fragmentation. For the technically inept shouting how MS is spying on them, the info sent is way less than what your Android/iOS is sending back home or you willingly post on the internet. It mainly consists of behavioral and application usage data, for statistics regarding what settings are changed the most, what and how is used and for how long. Every service in existence which is not enterprise oriented, does that transparently or not.
I'm not into the bandwagon, and even I know it is a bad OS. Aside from the plethora of privacy concerns, many of which are way too ambiguous to even be examined, there are a lot of compatibility issues with legacy software that result in a lot of broken applications and complaints about this on services such as Steam. Telemetry and other intrusive environments do not help matters, the updating issues reported since its pre-launch release are evident in articles and videos by users, the UI changes the overall workflow too drastically to reinvent the wheel when the wheel was just fine (such as Win7), and there's too much involvement/dependency on the cloud, which aside from the obvious privacy concerns can also suffer from connectivity issues. All of my points only scratch the surface. Deep down Win10 is not a viable OS compared to its predecessors. It has succeeded in being the unwanted follow up that Vista was, and like freak777power said, I and many I know and discuss this with are eager to see this misfire laid to rest so we can see if the next OS MS hatches will be a better, safer, less intrusive experience.
I'm an IT professional. There are things I like about 10. However.. every single machine that I work on gets a thorough lockdown. I disable all the useless apps, error reporting, telemetry, Cortana, etc., install Classic Shell... I'm sure there will be more useless bloat in the future that I'll take pleasure in circumventing.
Windows 10 is a great OS, anyone complaining about Windows 10 is ignorant. Go ahead and install any variant of Linux and you will see a lot of bloatware installed along with some of the ugliest UIs ever devised with almost no flexibility in layout. I went from Windows 7 to Windows 10 and would never want to revert to the former.
Aside from that. MS needs to separate Edge from Windows. MS is spending too much time trying to get Edge functional and it distracts them from making the OS polished. Edge is only likely to garner a following from ignorant Windows users who use the apps that come installed on their PC instead of investigating better software.
MS doesn't include Office as a built in app on Windows 10 and shouldn't include Edge. In fact the Education edition of Windows doesn't include Edge.