I would say that the same game can be played and dmed according to all the styles.
you said you run a 3.x game where you did lots of preparation, but then it ran smoothly and you never had to look up stuff. i suppose it's possible to do so
myself, when running 3.x i do it more atlas-style, because every week a player comes up with a new trick he wants to use, or perhaps i come up with a new trick to give an npc. or a player would try something really unusual during a session and i'd have to figure out how to handle it mechanically. either way, it's a continuous work, and i can't conceive dming any other way.
while i can totally see a group of casual players sticking to the simple rules, just making attack rolls and using simple spells, and never needing to stop to adjudicate something. i was in one such group as a kid.

so, it's a group style rather than a feature of a game system