1. What metrics do you use and rely upon consistently?
For holistic hitting performance wOBA and OPS are both fine. Both correlate well with runs scored. I prefer wOBA because it is created from the run values of the events that happened, whereas OPS is just a random combination of OBP and SLG.
wRC+ is preferable to both, though, because it is park adjusted. wOBA is not! And neither is OPS, of course. So you can weed out things like the Coors effect by looking at wRC+.
Another advantage of wOBA over OPS is you can compare wOBA directly to xwOBA, which is their expected wOBA based on the fancy statcast stuff like hard hit rate and batted ball profile. So wOBA gets a leg up in utility in the era of statcast and baseballsavant.
So for holistic hitting performance (i.e., "how good has this guy been?") I am mostly looking at wOBA and wRC+.
If I went to go a bit "under the hood" I will look at xwOBA, BABIP, K and BB rates, barrel rate, maximum EV and average EV, launch angle, and batted ball percentages (GB%, etc.) These all help answer the questions of "how indicative of actual talent is this player's past performance?" and "how good should we expect this guy to be going forward?".
For hitters, all you need to really look at after wOBA/wRC+ are their BsR and UZR on Fangraphs. Layer in the positional adjustment and all of that stuff together = fWAR. Note that "Def" displayed on the Fangraphs dashboard is UZR + the positional adjustment. I don't really look at baseball reference WAR for hitters, ever.