Even though the title suggests different, there are basically no just good or just bad unique buildings (and units). Every UB and UU has to be evaluated in the context of the game settings and overall strategy it´s supposed to be used in. A (fictional) unique unit archer that gets +100% against melee units is useless in an game played on Islands, where you have no (military) contact with your opponents until Astronomy is researched and archers are long obsolete. A unique building is good if it significantly supports a (playable) strategy.

Bad

Salon
Unique building for the French; Replaces Observatory



+25%
+1 free artist
Can turn 1 citizen into scientist
Required to build Laboratory

This is one of the worst UBs in the game - at least on some settings. Unlike other bad unique buildings the salon does not only not support any kind of strategy, it actually is very counter productive in some setups. At first glance you´re getting a free specialist - remembering that for example the Great Library gives you two free specialists and that makes it one of the potentially strongest wonders in the game for many setups, this could be good.

First drawback is the required technology; Astronomy is a mid-game Renaissance / early Industrial technology. So we are looking for ways of using the Salon in a Renaissance/Industrial game, most likely a teamer or obviously in an Ironman.

In teamers first of all France is not the civ you pick for making Great People. Due to it´s Unique Unit, the French Muscet, France is picked in Renaissance start games. Beyond that, the unit is useless or not available. In Renaissance though you want to focus on spamming as many of those double-move muscets as possible ´cause next to your team mates´ Knights it is the only unit that gets defense bonus and can defend against pikes during your attack, hence no time for GP making. Also being Philosophical (non-Philo making the GPs makes no sense) robs you of either a muscet-enhancing agressive or of a necessary spiritual trait. In addition observatories come only during mid/late game, at least are not available from the start.

In an Industrial start where they would be available from the start, muscets are obsolete. Now investing 80 hammers for a free artist for a culture bomb might be worth it at the beginning of the game (Don´t forget though, you gave up another civ for France, though you could be Philosophical now). You´d get your first artist maybe a little bit faster, but probably barely. Being Philosphical working 2 artists results in a 6-turn Great Artist anyway and you can do that with a pop 4 city with a threatre. Even if there was a benefit, you are now stuck with Artist GP-points in your GP pool for the rest of the game. The free artists - just like with Great Library for example - can´t be not worked. So if you want to get a scientist to bulb something that requires one, you have a good chance of getting an artist even if you yourself only work scientists.

Imagine an Ironman, where Observatories are a key building, which almost every city gets. Without Representation artist specialists provide one measly science and some useless culture, on the other hand your GP pool gets polluted in every city. Artists are the worst GP you can get in an Ironman since they neither accumulate (significant) Research nor Commerce nor even production. Getting a single Great Artist instead of a Great Scientist to settle in your capital is worth the amount of extra tech you are generating with those free artists combined in an average Ironman already.

Good

Hippodrome
Unique building for Bycantium; Replaces Theatre



+3
+1 per 5% rate
+1 from Horses
Cannot turn citizens into artists.

This theatre is all about happiness. There are two main, wide ranging ways of using this building and all three don´t care about the drawback of not being able to work artists unlike in a normal theatre. Notice first that the Hippodrome gives your empire +1 from Horses istead of from dye like a normal theatre and horse is a strategic ressource hence always available in multiplayer games (unlike dye) which are played on balancd ressources (one horse, iron, copper, oil etc.) in a relatively short range to your starting units, mostly up to 5 tiles in any direction.

Both strategies take advantage of the easily accessible happiness the Hippodrome generates.

Medieval

Lately Bycantium has been banned from the CCC medieval tournament due to its strength (though the culprit here is mainly the caraphract) - having a clearly more powerful and its strategy one sided civ in a setup can become boring overtime and so a change is sometimes forced via a ban.

Get as many cities as possible (around 5-6) with barracks, stables, forges, preferably religion (if you get one) and Hippodromes until your team researches Guilds. Then slave out Cataphracts the rest of the game, not having to worry about happiness due to your UB - if necessary just turn the culture slider to 10% or 20% and you´re fine.

Industrial

This is where the Hippodrome shows its strength to the fullest. An Aggressive/Spiritual Montezuma of Bycantine gets a couple of workers, farms most his land and switches to Nationhood to draft Rifles. Usually the unhappiness resulting from drafting in the same three cities (the three from the 3 starting settlers) every turn would result in lethal unhappiness very fast, stopping or at least very weakening the plan of getting enough rifles super fast in order to rush and kill an opponent. The unhappiness goes so far that even if an opponent dies, the Bycantine player first has to recover and switch to a less devastating way of production. This is a skill and experience demanding slot, but if played correctly and not perfectly defended by the opponent can be very rewarding.

This strategy, applied in this extreme way is unique in the civ world and woulnd´t be possible without the Hippodrome.

For Good UB - Bad UB part #1 click here