Tier 3 buildings are just fine, to get Eurekas and Inspirations. Otherwise they are generally a bad return on investment, producing less benefit than what you put into constructing them and what you could have gotten if you had put that production elsewhere. Some opinions have to be taken in context of the level you play at. At Emperor, if you don't win by Turn 300 the AI probably will. Immortal, Turn 280. Deity, Turn 250. These are old, pre-Gathering Storm estimated numbers but the point stands; you are racing for victory. The higher the level you play at, the less tolerance for pleasant diversion while still trying to win. Hey, I love my Wonders. Which is one of the reasons why my wins are in the Turn 220-260 range. If I knuckle down I can get sub-Turn 200 wins on Deity but it's an accomplishment without satisfaction, not what I want in a game I play for entertainment. YMMV.