I hope everything is well for you.
Large pros
-have tons of selection on fish, choose whatever tangs you like

No tang police around your tank.
-more corals to put in your display.
-SPS growing/space is not a problem.
-have a paranoma view.
Large cons
-large amount of $$$$$ spend every month including salt, water bill, electricity bill, chemicals.
-have to put a lot of show size piece corals.
-take longer time to build a complete tank as your desire.
-space/moving considerations (pain in the butt)
Small pros
-saving you $$$$$ on coral, salt, chemicals, fish.
-easy to manage/take care.
-water change is not a pain in the butt chore.
Small cons
-every coral must be a show piece due to space
-no big fish
-SPS growing is a problem later on.
Hope that helps you.