My opinion is based on a few things like, full sus vs hardtail, dropper or not and the type of terrain you are riding.
Flat terrain, keep saddle close to road position. Lots of climbing, saddle forward and nose down. Dropper post, run saddle same height as road bike, no dropper, lower it a few mm. Full suspension, adjust saddle position at rider sag, not static with no rider weight - this makes a HUGE difference. Bars height, about the same as road bike, there are arguments for going up (better descending) and down (to deal with steep climbs), but it's highly personal.
My school of thought is you want to be positioned optimally where you are going to spending time pedaling....on a MTB that is generally while going uphill, where a road bike is generally on flat ground. So I try and set mine up with a more forward position and aggressive position so when I am on a climb, it's similar to my road bike on the flats. I also find a more forward position helps with transitioning from sitting to standing and vice versa on steep punchy climbs.
Obviously if you live somewhere flat, you probably want more of a road position.