Depends on the story line. Before the 18 year leap Nausheen was the perfect Kkusum. But for after the 18 year leap...I think Mansi was the best Kkusum...cuz she didn't look too young nor too old...she actually looked like Kumud's mother...and now that Kkusum has gotten plastic surgery...it was proper for Shilpa to come in...so basically u can say that what I'm saying is that all the Kkusum's were good...they were brought in at the right times according to what the story line was...