All these points i am mentioning here are for IISC:
1) Placement : No need to worry about it , you will get the best.
2) Research : Do i need to say anything about it.
3) Faculty Interaction : Faculties are very good and helpful, When you join IISc the department provides you a Faculty advisor that helps you in choosing subjects and helping you in every sense.
Same as faculty advisor you will get Student advisor also who will be from your senior batch who will also help you.
4) Campus Life : IIT B has an edge over it, but if you know how to enjoy then there is not much difference.
IISC is not about always studying :p
5) Course Load : Load will be heavy in IISC, There are no hardcore courses you are free to choose any courses you want but the condition is you have to complete pool requirements.
6) Auditing : Any number of courses you want
7) Alumni Network + Brand Value :Both are awesome
8) UG : Come here and try to mess with them you will come to know :p
9) TAship : Not required
10 ) Location : Bangalore is good place to be.
11) Others :
1) Mess Food : It is ok-ok not that good not that bad.
2) Hostel Rooms : Single rooms will be given to M.E guys and rooms are good.
3) Internet Connectivity : No internet in rooms,if you want you can take your own connection.
P.S : Every one has there own perception about both the colleges, every time you ask this thing from a new person you will get confused.