Hi and many thanks for your reply.
the cost of the PCIe SSD was already in the budget and have sufficient funds for covering up to €180 (+/-) expense. Cable is not an issue but if I can avoid passing two extra cable I am happier (personal preference that has no impact on final decision). I was just saying...
The chosen Asus X99-A II motherboard has 1 x M.2 x4 Socket 3, with M Key, type 2242/2260/2280/22110 storage devices support (Support PCIE SSD only). So, no Sata Interface here available.
I tried to further document myself on the Internet and learned that PCIe is more geared toward projects involving handling of large data files and video editing where read/write is very frequent. For the rest is mostly identical, in response time, to a regular SSD.
This new PC assembly has a decent GPU and CPU with already sufficient RAM. At present time it serves the use of live streaming but I am certain that sooner or later I will end up doing some video editing or graphic editing: this is my perception.
This is my concluding thoughts: if I have to spend around €100 (+/-) for purchasing a decent SSD (I like Crucial MX300 despite that TLS NAND) or even a SanDisk why not spending a little extra money and get something that would at least equal current SSD preference but preserve me future enhancements? I would have agreed that between €100 and €400 (for a real good SSD PCIe NVMe) there is a huge gap but for only €81 more I am sure I will end up having invested my money in an SSD that will allow heterogeneous projects for this workstation.
I am also happy to notice that even Microsoft is using this PCIe SSD (under the brand name of Toshiba - but identical to this OCZ) for their Surface 4.
So, OCZ (RVD400-M22280-256G) M.2 256GB" is what I believe the prefferred decision to take.
I am sure to have done not only a valid choice but also followed a valid thinking.
I hope this thread will be useful to those users who might have the same/similar question.
Thank you for your support...