Orgrimmar.
My alts are still set to Shrine. I gotta get around to changing that at some stage…
The Great Seal. It’s convenient incase I need to take a portal to take another portal somewhere.
I’m a mage, the hearthstone is mostly for show. Nazjatar at the moment, maybe save me a click.
Wyrmrest Temple, of course
Boralus.
it’s a decent town with some good food.
With so many quick and easy ways to get to Boralus I’m not sure why anyone would waste their hearthstone on it. Mine’s set to Grimwatt’s Crash, which is centrally located on the island of Zandalar. That gives me quick access to the world quests and the dungeons there.
Orgrimmar. Always.
Currently Orgrimmar or Ironforge for the Abominable Greench quest.
Usually it is set to Boralus or Zandalar.
…but why?
Literally no real point as they are all connected. Don’t the goblin’s charge higher rates even?
Aside from my Mage’s Boralus Harbor/Zuldazard (where I can just teleport there) its just easy to get the the hubs and have portal access.
As for my mage its always in some far off place for quick access for farming.
Rustbolt. Not really sure why anymore, but when I want to zap to Boralus I use the Commander’s Ring to do that.
Alliance: Boralus (whatever the main inn is)
Horde: Spirits Be With You
My damn house is where mine set at
mine is set at
On my mage, somewhere close to Goldshire. Well, you can guess why 
Mine’s still set to Zandalar/Boralis for my toons.
/narrows eyes
You don’t need to know this…
it was set there well before the AHs were combined, back in 2011. back then the goblin AH was the only way to move items to my alts on opposite faction (using two accounts)
on this mage i just haven’t had a need to change the hearthstone target ever since
travel is one of the worst grinds of an MMO, wow included
got hearth set for boralus near the portals
got ring to port to dalaran
got the engineering porting trinkets for another 4-5 zones
got the gear slot to teleport to stormwind/orgr
got the garrison hearth to port to WoD
I think I have a couple more shortcuts as well
Snug Harbor Inn.