Hi,
the Mini has SATA3, so ist can profit of the best Speed the SSD can provide.
The 850 EVO is a little bit faster and has 5 Years of warranty, the MX200 has more GBs.
I can tell you that I have bought the well-review 850 EVO (cause of the 5 Years warranty) and Im happy with it even if my Mac Mini 2006 can not rudimentary use the Speed of the SSD but profits a lot of the fast responsive-time.
It feels like a new mac