I would much rather play slow.
I'm only into my 3rd generation, but I play my games in rotation, and I have 7 saved games so far. It's already 4 months since game came out.
I feel like if I go too fast, like some ppl, that I'm going to miss something. About the only time I use the one speed faster than normal button is when sim is studying, or is still a new gardener.
There is so much detail in this game that when you play too fast, you're gonna miss something...but to each his own. Everyone plays the way they feel.