Thanks for asking! I wanted to write it up this weekend but as you are asking now I can provide latest news here.
We decided to go with Intel 600p SSD and our warehouse has 600 of them already and 2000 more are coming in few weeks.
Now the reason we did not to vote on SSDs is fairly simple, there was no other good option.
We have tested Samsung Evo 850, 960, Intel 600p and one more SSD that was an OEM version of Samsung 960.
First we have tested our SSDs for power consumption. And the rough numbers we got were:
Samsung Evo 850 - 600 mw
OEM version of Samsung 960 - 800 mw
Intel 600p - 200 mw
Samsung 960 - 65 mw
Under higher loads Intel SSD had the best power efficiency. So performance wise Intel 600p was second best.
Additionally when we looked into pricing Samsung 960 was almost double the price of Intel 600p (meaning its roughly 150 USD more expensive then Intel 600p for 512 GB version).
In addition to all that we would receive no optimization support from Samsung for tuning our SSD performance.
So as a result we went with 600p (we had to buy it really fast so that they don't run out of stock, there is a big storage shortage on the market now)
As for the second part of your question regarding encryption I would check with our engineering team and get back to you!