Some random and general thoughts on the subject. But when they are free to work (as in you have other buildings that grant a free urbanization point) and you have free population and there isn't an obvious normal tile that is better or on par. Then there are various special cases, such as if you are already unhappy then it might not matter if you get a little more unhappy as long as you don't hit another break-point. If you are building a settler you can pump in specialists since the city can't starve but always remain stagnant. Are some better then others? Sometimes and it depends on the game, perhaps it's more that some of them are just less useful or mainly useful at certain points of the game -- say if you don't run a a game where diplomacy matters why build great diplomats etc. But in some general way I say engineers, scientists (over all and in general I think they are overvalued) and writers (that said their value greatly diminishes as the game goes on) > the rest, or they at least usually fill an instant purpose while the others might be a more case by case -- does a city state want one for some quest, would it be nice to have one of the others to fill some kind of specialty task.
For an authority game specifically. Engineers to rush a few select wonders or build a tile improvement to grant more production so you can make more units so you can war more. Scientists are less valuable since you'll get science from war/killing/conquest that should fill that niche. Writers can still be good to push culture and policy matters. Merchant could be good if you have gold issues. The rest might not matter all that much.