I've been running the preview releases of Windows 10 on one of my computers and I've been quite impressed. And now I've got Windows 10 on my "proper" machine, my Surface Pro 3. It's very impressive. Boots fast and the user interface improvements make a huge difference. My advice for would-be migrators.
- Do it. I don't think you'll regret it. And if you do, it is very easy to revert back to your previous system. I've actually done the revert after I did something stupid during an upgrade and it took me right back to my original system in around five minutes.
- Give the machine time to settle down after Windows 10 has installed. Once the Windows 10 upgrade has worked its magic you get a whole slew of processes wanting to come in and tidy up. The Search Indexer, the Antimalware process and OneDrive will all want to do considerable amounts of twiddling on your new system. This can ruin user interface performance for a while as the hard disk gets hammered. But give it an hour or on its own so with a decent network connection and you'll see performance go back to previous levels.
- The Edge browser is awesome. Very, very snappy. In fact unfeasibly fast. And it seems to be compatible with lots of websites sites too. It works a lot better that Internet Explorer with the page editor for my Squarespace website, which is nice. Try it even if your weapon of choice is Chrome or Firefox.
- If your machine hasn't got much disk space you can recover quite a lot by using System Cleanup to get rid of your old Windows installations (see above). Of course, if you clear away this backup there is no way to return to the previous version but on very constrained machine you probably won't have a choice about doing this. I've upgraded my ultra-cheap Linx machine (very successfully) and got back three or so precious GBytes by doing this.
It will be very interesting to see where Windows 10 ends up. And I reckon that you really should go along for the ride.