Slightly earlier than expected by some pundits, Microsoft has now stated that Windows 10 - for PCs and tablets, at least - will arrive on July 29th and have kicked a process off by Windows Update to help users reserve and then be notified of actual availability. Some quotes are below, and all this is very definitely of interest - Windows 10 has been rock solid for me on my laptop. Don't get too excited though, since there's no word on timing for the Windows 10 Mobile SKU (a.k.a. what Windows Phone will become) - judging from the progress on the Insiders Build on various phones here, I'd say we're looking at least two months behind the desktop SKU. Then you have to add another month or so for approvals, at least if you want official firmwares. Which takes us to the end of October 2015. Or so.

From the Microsoft article:

Today, I’m excited to share the availability date for Windows 10. 

....In addition to these innovations, we will continue to update Windows 10 over time with new innovations to help you be more productive and have more fun. Like Windows 10 itself, these updates will be free for the supported lifetime of your device.

...On July 29, you can get Windows 10 for PCs and tablets by taking advantage of the free upgrade offer, or on a new Windows 10 PC from your favorite retailer. If you purchase a new Windows 8.1 device between now and then, the Windows 10 upgrade will be available to you and many retail stores will upgrade your new device for you.

The Windows 10 upgrade is designed to be compatible with your current Windows device and applications. We are hard at work to make this upgrade process a great experience. You can reserve your free Windows 10 upgrade now through a simple reservation process. Look for this icon in your system tray at the bottom of your screen, simply click on the icon, and then complete the reservation process. You can find more details on how this works at Windows.com.

Thank you for choosing Windows. We are designing it for you, so you can be more secure, more productive, have more fun.

I'll certainly be upgrading our laptops to Windows 10 - one is already on the Insiders build. On the phone side, I have three phones up and running on the Windows 10 Insiders Preview - and I can say that things are a lot smoother:

1. with a Snapdragon 800 and 2GB of RAM (on my 930)
2. if you bite the bullet and hard reset after upgrading to the preview. Without legacy cruft and settings, the experience is much better

In fact, the next Insiders Build may see me switch to Windows 10 Mobile as my primary smartphone platform - at least, until I hit a showstopper. I'll report back on the pages of AAWP, of course!

PS. Of course, even though I qouted end of October 2015 above for Windows 10 Mobile to appear as an official upgrade for existing devices, there will be the usual earlier opportunity for brand new devices, shipping with Windows 10 out of the box. I'm expecting a Microsoft event to announce new Lumias in July and softer launches from manufacturers around the world between June and August, with the first hardware shipping in September.

PPS. There's a video too, with Windows 10 Mobile making a short appearance: