I got a used late 2011 Macbook Pro 13 for my niece. I replaced the existing 500 GB mechanical drive with a 240 GB 840 evo and I'm quite happy with the results. I made sure to upgrade the evo to the latest firmware, enabled trim in Sierra, and installed office 2011. I have used it for about 20 hours in total and haven't noticed any problems.
Anyone know what sort of problems may crop up with this evo? I was using the evo in a desktop windows machine for about a year before moving it to the Macbook.