I bet you couldn't see any difference without carefully benchmarking or measuring your daily tasks. But there are differences of course. They just happen to be so small, and in both directions.
If googled: EVO vs EVO plus, you can see that besides max speeds EVO Plus has got better IOPS numbers than EVOtoo (approx. 20%).
Then again, in some tests plain EVO wins by a little margin.
When last time buying a NVMe, I chose EVO, because I would not want to worry about any firmware flashes. There's not so much of a difference there, but then again - there might be a difference for some folks.
If you want or need more speed than the above mentioned 1500 MBps, you'd need something like
IO Crest Syba SI-PEX40129. To find out more options, please read the first post of this thread we are discussing at the moment :
Blade SSDs - NVMe & AHCI
In my opinion this IO Crest is a little bit noisy though. I believe it needs this extra cooling because of the switch chip in it, I think. To get all the potential extra speed with IO Crest and the likes, you need to sacrifice a 16 x slot for it, a.k.a slot 1 or 2.
I am thinking to downgrade my main machine from Syba IO Crest to Aqua Comp Kryo at the moment. I thought I could take the extra fan noise, but I'm not quite so sure anymore. I already took away my other card, and put the IO Crest to slot 1, and RX 580 to slot 2, other slots empty and left Mac Pro without the in between PCIe shield backplates to let air flow through better. It didn't make much of a difference. I guess the fan rotates at a fixed rpm in an IO Crest card.
O, I could make a little cable hack published by a forum member earlier:
https://forums.macrumors.com/threads/blade-ssds-nvme-ahci.2146725/page-43
That is if I dare to.