Similarities :-
1. Both asher and khirad r first cousins jst like zain n aaliya.
2.Both asher n khirad were poles apart jst like zaya in terms of lifestyle n money.
3.The reason y d lead couple splits is due to a third party meaning khizar / zubair.
4.both the lead couples get married under pressure of herione's mamu.
5.Opposites attract theory starts after marriage.
Difference :-
1.in BI , only MIL is the main vamp while in HS , MIL, asher's childhood frnd sara n her mom r d vamps.
2.There is no barkat or rehan like charater in the show 😆
3.The reason y khizar says bad abt khirad n cause misunderstanding is smewat understandable ( khirad luves sara n sara luves asher so u understand y.. 😉 ). But reason y zubair is supporting surraiya is so stupid n doesnt make any sense at all
4.asher ws a workaholic frm begining itself while zain started going to office after marriage.
5.In HS , mamu dies while in BI , mamu is currently in wheelchair.
6.Before marriage asher n khirad hv met only once whereas zain n aaliya hv met quite a lot of tyms in childhood.
As of nw , only these many things have caught my eye 😆 . The moment i find more , i ll update soon :-)