Only if you want to risk less compatibility and stability. Windows 10 right now, is still not as stable as 7 or 8.1, although major issues tend to be related to what you install. Some hardware such as graphics cards, printers etc may no longer work in 10 at all, and drivers to install for old hardware may never be available. Google to find out if all of your hardware will work in 10 if you are concerned. Youtube has lots of examples of the windows 10 installation going wrong, or people showing their hardware problems. My own installation took a very long time, so be very patient, even if you think it has crashed, leave it! My own system installed 10 and booted to a blank screen with cursor. I have integrated intel graphics. I had to install windows 10 compatible drivers for 10 to work properly after that.
SECURITY
Heavy windows security tools such as Avast and Comodo have been causing headaches for many. I have had numerous problems with the windows 10 desktop disappearing and the start menu not working when I click, but it all came down to the two programs I mention above. After a lot of testing, Bitdefender, Panda, AVG, Eset (30 day) all seem to work ok. Avira was on the system briefly too although is quite heavy on the system, and I dont know if random crashes will occur as with the two programs I mention.
I haven't tested many firewalls, there aren't many free options so make sure you stick to something light if you don't want to run into too many problems. I am just using windows firewall at the moment, which is good enough as long as I only go on websites I am familiar with, that I know are safe. There are tools that can help windows firewall block programs access the internet such as Glasswire, Windows Firewall Control and Tinywall, although as free software some might not be blocked until they've run at least once, or might block too much if you are not technical. PrivateFirewall is a very light firewall that might also be worth a go, but in order to be very secure you will encounter many pop ups. If you are running suspicious software, try running it with Sandboxie and make sure you have an antivirus installed.
Before installing 10, you might want to back up an image of your current windows 7 or 8 to another hard drive, if you have a spare one around. Or copy all of your most important files such as documents and other saved files to another computer, hard drive, usb stick, or if you don't have a lot, even dvd, before installing 10.
Windows 10 is similar to 7, 8 and 8.1, as they are all a derivative of Vista (windows 6). They are really the same system, but as with each major update, microsoft simply sells it as a 'new operating system', when in reality it is not. Windows 10 is an update of 8.1, using the exact same colourful Start metro interface, which can show in full screen or as a menu, to view the start content and apps. You also have the option of a tablet mode, which lets you close windows and programs in the same manner as windows 8 (holding left click and dragging from the top of the page to the bottom).
The default Start menu in 10, is 8's start screen, squeezed into a single column on the left. They are near identical as if you are not on a touchscreen, you will need to use the scrollwheel on your mouse to browse the menu. It is still not the traditional start menu you had in 7, as you cannot drag and drop items within it, and you cannot view folders (although you can browse to any shortcuts location in explorer, showing the folders). To solve this and get your original start menu back, install Classic Shell.
Apart from a most features kept from 8.1 such as multiple desktops, and some new ones few people may use (cortana) it is really still the same operating system, except it is less compatible and less stable, especially with security software. If you hated the look of 8 you may not like 10, but again, classic shell will help solve that (it works in 7,8 and 10). Good luck!