Using Object Repository is a advantage or disadvantage?

As far i think both of them have their advantages and 
disadvantages.

OR is simple and easy to identify the objects. but it 
consumes too much of memory when it is loaded and it will 
increase the execution time. And if you have multiple 
object of similiar kind of object properties at times it 
will fail to recoginzed and the script will fail.

But DP reduces the execution time. Script will not fail in 
this b'coz ur just changing the required property of the 
object, yes it true that initial work more that creating 
object properties list in an excel sheet and load that 
excel sheet during runtime. but this can be overridden buy 
using XML file which is less in size and Quick in loading. 
and it takes very less memory.

let me know if you have any comments on this.