Thanks for the discussion above!
Purchased the 500GB 860 EVO, the price was about $14 higher ($67.95 shipped, yet my Amazon rewards dollars earned as a Prime member with their card (5%) was nearly $18, so the cost ($67.95 shipped, will arrive tomorrow) was less than WD Blue, of which was considering as well. Have several Samsung SSD's (plus 5-6 of their HDD's before Seagate took over the brand), all except one has ran perfect.
The one which gave trouble with read speeds, a 250GB Samsung 840 EVO, I run their tool on it once monthly, or when I notice slowness. Although the free Disk Fresh tool ran with Read Only option checked gives better results, takes longer. Oddly, the 120GB of the same model runs perfectly fine. Back then, 500GB SDD's were expensive & somehow managed to clone the 1TB HDD installed in XPS 8700 when new to that 120GB model, even recovery partition & left 10GB for over provision. A week or so later, Dell sent me at no cost a reinstall DVD, this helped greatly. Back then, a 120GB 840 EVO SSD cost more than a 500GB 860 EVO of today, a lot more, I believe $119 on Newegg promo.
Didn't really want another 2.5" SSD, but the laptop doesn't have a NVMe option, otherwise wouldn't had to purchase anything, as I have a couple spares. As far as 'wearing out' goes, my first SSD, purchased in 2012, the 128GB Crucial m4, still has 98% lifespan left, and 2nd a few months later, a 180GB Intel 330, amazingly shows 100% by their Intel SSD tool. So these drives aren't fragile anymore by a longshot! Hopefully the trend will continue.
Also didn't want to be stuck with another DRAM-less SSD by Crucial which I assumed to be on promo. Although the Crucial BX300 hasn't given me any issues & is OK in a rarely used SATA-2 notebook, never occurred to me that Crucial, one of the leading manufacturers of RAM, would sell a SSD w/out physical DRAM. In fact, up to that point, had never heard of such, so sure wanted to avoid it this time & also no QLC. I expect MLC to go the same route as SLC & TLC to be on most premium drives, QLC for budget. Speaking of which, when the 840 EVO was purchased, TLC wasn't favored by many, so QLC has a year or longer to go before widely adopted. Hopefully Samsung will keep MLC in their Pro series 2.5" & NVMe lineup, if not, customers won't pay the markup.
Again, thanks, this article guided me on making the right decision!
Cat