SSD (2.5") vs M.2 for OS drive?

[Legend]

Looking at the 250GB size for an OS drive (games on another drive, so this would be general desktop apps etc). Is it really worth spending the extra on the 960 EVO M.2? I know the figures speak for themselves and the M.2 is quicker, but in real world terms is it REALLY going to be that noticeable and worth the 40% price difference (the 850 can be had for around £84)?

Samsung 960 EVO Polaris 250GB M.2
Samsung 250GB 850 EVO SSD 2.5"

 

[Telecaster]

Whilst not a 960 EVO, my boot drive is a PCIE M.2 drive and I can't tell the difference between that and a decent SATA SSD. I only really did it to save a bit of space and cable clutter.

 

[HoneyBadger]

Real world you will not notice the difference. Try a search, this comes up a lot!

 

[schneeb]

I recently got a samsung 750 "500gb" (more like 450 actual) as my previous two 250~ drives filled up instantly, in my opinion just get the largest SSD you can and avoid the high performance ones (nvme, m.2 can be sata); it will still be miles faster than HDD.