In 4th and 5th gen I mostly did competitive using battle simulators until RNG abuse became widely known. After that I just RNG'd pretty much anything I wanted or needed outside of shinies.
With 6th gen turning the mechanics on their head and making everything a lot easier to deal with I just go full legit breeding, since once you get a decent collection of parents together in various egg groups, it's extremely easy to get whatever you want.
I mostly owe my breeding success nowadays to this group of little bros. (Well, until I get off my butt and RNG a 6IV Flawless Ditto anyways.)