Continuum is right in the limited stock as reason for price, however in your scenario (OS+apps) you will see exactly zero difference in performance between 840 Pro and 850 Pro (I have both in my main rig, the 840 Pro is 3 yrs old, the 850 Pro is 10 months old). The 850 Pro is expected to have double lifetime (6000 write cycles vs 3000) but it is very-very unlikely that with OS+apps you will get anywhere near to their limits. As for 840 slowdown: it happened to 840 EVO and 840 only, there was no such problem with the 840 Pro.
Whole lot of marketing BS. Writing multiple times 3-bit SSD, 3-bit NAND MLC and so on only to avoid the dreaded word: TLC.
Compared to what? Certainly not MLCs.
Yeah, on par with other SSDs and for sustained writes well below the competition.
Based on consumer market experiences of 840/840 Evo it won't happen. Data center managers are not known for their purpose to choose TLC over MLC/SLC. Especially when they check lifetime of TLC vs MLC in heavy usage environments and calculate TCO.
The quoted text you copied is dumb stupid. The Seagate 1.5TB has (or had?) design/firmware problems which has not much to do with platter density. Also Samsung's HD103UJ was a leap in the dark by Samsung who had no previous experience in top edge (market leader) technology of this kind (in field of making HDDs, I mean), so no one was really surprised when it turned out that the first products weren't so flawless. As for general medium quality of today's drives - let me disagree. In the past the ratio of broken HDDs was not lower in general mass market regarding what I saw and read (I started to use HDDs in 1990 and have tried to follow trends in storage since mid 90's). So far I had 3 drive failures (a 15 GB IBM years ago - BTW top quality in that time, a 300 GB Maxtor - no surprise here and a 40 GB Samsung - which I dropped from 1.5 m, uh-oh), and have no problem with my 4 1TB drives I use (2 of them in 24/7) - two is WD, one is Hitachi and one is a Samsung HD103UJ . So much for individual experience and showing it as general knowledge.
Remember, last year Samsung F1 data was seen first on German webshops - months before the actual HDD was on sale. So leaked info can appear anywhere, see this link, where I too thought the F1 to be hoax Link.
Nevertheless this current WD-thingy is a little too weak on info to be realistic.