You've got questions, and because I've been running Windows 10 on my Macs since the earliest builds were made available, I've got answers for you.
Does Windows 10 run on a Mac?
Yes. I've installed the release build on a number of systems and on the whole it's been a smooth and buttery experience.
What Macs will support Windows 10?
It's hard to pull up a definitive list, but I'd say based on my experience that any Mac sold in the last five years should be fine. See below for how to run the compatibility checker if you're in any doubt (note that your Mac will need to already be running Windows 7/8.1 to do this).
Does Windows 10 run in Boot Camp?
Windows 10 is not officially supported by Boot Camp, but everything seems to work just fine. In fact, it's probably one of the best systems that I've run Windows 10 on, and I'm not alone in thinking that.
Fire up the Boot Camp Assistant to get things going.
Any Boot Camp tips?
By default Boot Camp suggests you give Windows 16GB of disk space, but I recommend upping that to 25GB to give your installation room to breathe.
Does Windows 10 run in Parallels Desktop?
Yes, but you need to have Parallels Desktop 10. Other than that's it's been a flawless experience for me.
Does Windows 10 run in VirtualBox?
Yes. And it's pretty easy to set up.
Does it run in VMware Fusion?
Yes, but you need to be running VMware Fusion 7.
Any virtual machines tips?
Give Windows 10 at least 2GB of RAM, but if you're a high-roller and have a Mac with 8GB or 16GB of RAM then I suggest giving Windows 10 at least 4GB. That's basically the only thing that I've noticed make any difference with how smooth the OS runs.
I've got Windows 7/8/8.1 running in Boot Camp/Parallels Desktop/VirtualBox/VMware Fusion. Am I entitled to the upgrade to Windows 10?
Yes. In fact, if you're fully patched, you should have already seen the "Get Windows 10" icon in your system tray.
Help! I'm not seeing the "Get Windows 10" icon in my system tray. What do I do?
Check to see if you have updates that need downloading and installing. That usually fixes things.
All the updates are installed but still no "Get Windows 10" icon. What else can I try?
Try this. (This is not Mac-specific and will work for anyone who's having this problem.)
I filled in the "Get Windows 10" thing but haven't yet got Windows 10. Anything I can do to jump the queue?
I've tested this process and it seems to work. (This is not Mac-specific and will work for anyone who's having this problem.)
Can I check for compatibility issues before upgrading a virtual machine or Boot Camp?
Yes. Details here. (This is not Mac-specific and will work for anyone who's having this problem.)
Where can I download the Windows 10 .ISO files?
From here. Bear in mind however that new installations will require a product key. (This is not Mac-specific and will work for anyone who's having this problem.)
Do I need to back up my data before upgrading?
Only if you care about your data. I've done a lot of installs and reinstalls and not lost any data, but I also make sure I have a backup just in case things go wrong.
Any tips to make Windows 10 even better on a Mac?
Yes. Install Trackpad++. This is a third-party Windows driver for Apple's Multitouch and new Force Touch trackpads found on MacBooks. Not only does it support 2, 3, and 4 finger OS X gestures, but it also supports Windows 8/10 gestures, and has the ability to detect and ignore accidental touches of the trackpad.