In first approach we need OR.We have to add objects to OR by record and playback or manually. Then we can write scripts
then run the test and we can get the result. So without OR we can not do the first approach.
In the second approach we no need to use OR. instead of using OR we tell QTP about Object's description write the scripts and run the scripts then we can get the results.
First approach needs OR.
Second approach needs Object's Description.