"Best Mainstream SATA SSD = 860 EVO. Alternative = MX500"
As usual, Samsung's regional pricing complicates things. Eg, in the UK, Crucial's MX500 2TB is over £100 cheaper than the 860 EVO 2TB (more than the 850 EVO vs 850 PRO difference used to be). Or in other words, Crucial 2TB MX500 is only +55% more expensive vs 860 1TB for +100% capacity at virtually same performance and 5yr warranty (and Crucial generally having a much more pleasant RMA process putting it politely). If high performance matters, you buy an M2. If capacity matters more, you get the MX500. Can't ever see when I'd buy that awkwardly priced "between a rock and a hard place" as first choice until Samsung trims a good 15-20% off their price inflation.
"Best 2.5" Portable Storage = 250GB external SSD"?
At capacities that low, you might as well buy a large 256GB USB stick. Given external secondary / backup storage is typically non performance driven, how about an actual "Best 2-4TB portable 2.5" HDD" option that's actually useful as a backup drive without running out of space 6 weeks later (yet is still pocket sized and doesn't require bulky 3.5" powered units of +6GB requirements)? Likewise boasting "hardware encryption" isn't always a good thing. If the external USB-SATA controller (but not the drive itself) fails inside a sealed 2.5" external unit, you can usually still pull a working drive and use it as an internal if it's unencrypted. If it's hardware encrypted, you're screwed for self-recovery. And yet for portable security, the drive itself can still be software encrypted if required.
Likewise, the age-old advice rings true -
don't make A backup, make 2-3x. Random electronic failures occur on everything (inc SSD's) and personally for backing up irreplaceable photo's or a lifelong music collection, I'd recommend someone get 2-3x external 2TB HDD's over same-priced 1x single 500GB SSD any day for redundancy / security with the quadrupling of capacity being icing on the cake.