Most Stable OS to run for mid-2012 macbook pro 13 inch with Intel core i5

Hi,

I have a mid 2012 macbook pro and I have been in the process of upgrading it with a new ram, battery, SSD, etc. I am new to using OpenCoreLegacyPatcher and was wondering if anyone could suggests which OS I should run on my macbook, preferably one that will run the most stable. I was also wondering if the patches are installed automatically or do I need to do it manually each time.