1) Windows 10 uses your bandwidth to send updates to strangers. Essentially, it bittorrents updates. Be sure to shut that off, or see your monthly data cap busted. 2) Targeted ads in the Operating System. Yippee! 3) Exposes your wifi network to all your contacts. Who needs a password?
and thanks to Hawkeye for pointing this one out: http://imgur.com/gallery/8OJ4t 4) Apparently, if you change any of your hardware, you could nullify your Win 10 upgrade license and have to buy the full retail license.
Even with Bing search disabled.. Windows 10 will "phone home" to Bing when you search from the start menu. In order to disable it, you have to configure custom firewall rules or change some group policy settings. Not everyday-user stuff to be tinkering with. Source: https://news.ycombinator.com/item?id=10037753
So is it even worth the free download or are you better keeping your old one? The advertising seems to imply it is "free for now" like there will be a charge down the road so I'm tempted to download it to my home PC... but then your reviews (unsurprisingly) are not overwhelmingly positive and make me think I'm simply better off keeping the old one despite the possibility of losing the "free" update.
I downloaded it to my Lenovo laptop, so that I could see first hand what it was like. I despise the start menu, but it's better than the Windows 8 start screen. I haven't had much time using it yet, so can't really form much of an opinion on the user experience.
But the privacy concerns are real, and if you value any degree of privacy, you're going to be stuck having to choose between that and continuing to use Windows.
The updates in question are KB3075249 and KB3080149. if installed, these updates are known to report your data back to Microsoft servers, without user interaction. KB3075249 Microsoft Update adds telemetry points to ‘consent.exe’ in Windows 7, 8 and 8.1, allowing for remote monitoring of everything that happens within the operating system. KB3080149 ensures that all “down-level devices” receive the same updates and treatment as Windows 10 boxes get. Below you can find a list of other Windows updates that some users have questioned KB2505438 KB2670838 – Windows 7 Only (corrupts AERO and blurry fonts on some websites) KB2952664 KB2976978 – Windows 8 only KB3021917 KB3035583 KB3075249
Frankly, OS X and Linux just became my only choice of PC Operating System. Even if you don't care about Microsoft harvesting your personal details, these back doors open avenues for hackers to exploit. You want your data going to thieves as well?