OSRIC / AD&D 1e was my choice of system when I returned to the GM's role after many years of absence. The two work seamlessly together, and I referred to either as my whims would have it. Can't say that about all of the OSR systems.
In this episode, I delve into OSRIC, which I see as the point in time where the OSR truly came into being. The first old school ruleset freely offered to the gaming community.Link to Episode #54 - https://anchor.fm/tavernchat/episodes/Episode-54---Delving-Into-OSRIC-e1p7in
Link to OSRIC - http://www.knights-n-knaves.com/osric/