They did ours really quickly. About five and a half months instead of the 9 or so months allowed, which was good and bad, as they rushed it at the end (we rushed them too so we could move in by Christmas) so the finish wasn't as refined as it possibly would have been. Time-wise could also depend on which supervisor you get. As far as I know ours is building display homes for Sekisui now.
With three kids darker carpet is the better choice!