Upgrade existing Win7 to 10, or install 10 fresh?

Ok so I know this isn't exactly a Win 7 question but... in a way, it kinda is. lol

So I have an option to upgrade my existing Win 7 Ultimate, to Windows 10 Pro... and its giving me the option to save all my data, files, apps, etc...

Problem is that before I do such an upgrade, I would want to create a back up of my Win 7 drive... but at present I have no space left on any of my other drives that can store the back up.

So either I just ..

Do it...

OR.

My other option:

My Win 7 is installed a Samsung 950 Pro 512GB m.2 SSD....

I have 150 GB free space.

I apparently only need 30GB to install the Windows 10.
So I take 100GB of that free space, and partition it as separate.
Install 10 fresh on the new 100 GB partition and set it as the primary boot drive.
Then gradually move things over, adjusting the partition sizes as I go...
Eventually, I'll be ready to wipe out the Win7 once and for all, the 10 partition absorbs whats left.

This second option obviously is a lot of work, but it would ensure a proper Windows installation on a fast SSD...

I am curious as to which is the safest option... has anyone here done the Upgrade option, and does it really save all your stuff, or do you lose anything?

The second option wouldnt work as it would put boot files in the wrong place and may not accept it as an upgrade as you would have 7 and 10 which you cant do on the same licence.
Just upgrade 1,0000 have done it with no problems just backup personel files first

Ok I'm confused then...

I'm following this article, which is how I found out I could still do this upgrade...

Here's how you can still get a free Windows 10 upgrade | ZDNet

It says:

If you're running the tool on a different PC, or if you just want more flexibility, choose the second option and save the installation files to a USB drive or as an ISO file.

After the download is complete, double-click the ISO file to mount it and open a File Explorer window; or, if you chose the option to create a bootable drive, open the USB flash drive in File Explorer and run Setup from there.

Is this no longer the case, or am I reading it wrong?

It seems to imply that I can create a bootable drive to install too.

My biggest concern about just doing the upgrade is that it will be an upgrade, on top of an upgrade, thats on top of another upgrade... starting from an upgraded Windows XP, upgraded to Windows 7, now upgraded to Windows 10, etc... my PC hasn't had a fresh installation of Windows in a long time.

Yeah truth is, there really isn't anything wrong with my 7 Ultimate.

Its just, old... and boots a little slow cause it was an upgrade over Windows XP Pro, that was cloned from a HDD to an SSD and upgraded from XP Home, and thus 7 was never clean installed.

Otherwise its been flawless and error free for quite a long time and has been the main rig on my little home network since forever. It gets pushed pretty hard as I use it as my primary gaming rig with some occasional video capture/editing on the side.

Perhaps I'll reconsider and do the upgrade instead, to my little Win 7 Home box, the one I'm typing/posting from... all its ever used for is net browsing, emails, and video streaming.