I'm in love with the OST of Heavensward. Be it Ishgard, the new music playing during some storyline quests, The Vault (and its final boss theme), one remix I certainly didn't expect and which is just awesome, the new primals themes and the last area of the game... I love them all, and I can't wait to do finish the story (leveled up 60 yesterday, but really needed to go to bed).(Matoya's Cave)
The OST is hit or miss for me - some of the music is fun, but most or all of it sounds like the actual music files being used are super compressed. Basically they just sound like fake instruments when the ARR OST usually had pretty good synth when real instruments weren't being used (which I assume is pretty much never)