For me it depends on which area you are looking for...for people who prefers this side or nearer to Shah Alam City would have known Alam Impian well...And sadly it also depends on which community u prefer to stay with...
Setia Alam can be considered matured area, since all the basic facilities such as schools, shops, etc are already up since it started way long before Alam Impian...Alam Impian can be considered new area with only several phases occupied...Its such a long way to go for Alam Impian...
And if i'm not mistaken, Setia Alam only sold a handful numbers of unit for its 'New Launch'...while AI sold a considerable number of units...
Even then, ironically, most of AI recent new launch, sold out within few hours as well...