So, I suppose it should never be left unsaid. Clean up your computer, backup your data. Then, if you must upgrade to Windows 10, go ahead. Sometimes it works flawlessly, other times, you’ll know the pain of a fresh new restore of your computer. You may be able to revert to Windows 8 (so I’ve heard, but I’ve not done it myself), but so far I’ve had no success with getting back to Windows 7 gracefully.
If you can wait, please do. Microsoft is allowing you up to a year to accept their free upgrade. By then, or maybe by Christmas, they will have worked out most of the bugs.