check syntax is not avilable in 8.2 check syntax is
available in 9.2 commenting is not available in 8.2
commenting is available in 9.2

Interface is a major difference.People who are very 
comfortable with 8.2 will find it difficult initially to 
find the options....Major difference is the object 
repositary...Drag n drop of objects from one hirarchy to 
another is possible....

Adv.s of QTP9.2:
1) we can rename checkpoints
2) can call multiple ORs in an action
3) can modify shared OR in OR Manager
4) OR size is increased
5) Function Definition option is avaialable
6) 'Screen Recorder' option is available in Test Results 
window

QTP 9.2 :
1)Object Repositories modes is local and shared 
2)Can call multiple Object Repositories in an single action
3)Object Repository Manager to manage all of the shared 
object repositories, this includes adding and defining 
objects, modifying objects and their descriptions, 
parameterizing test object property values, maintaining and 
organizing repositories, and importing and exporting 
repositories in XML format.
4)Built-in function library editor
5)Mercury Screen Recorder: Capture your entire run session 
in a movie clip or capture only the segments with errors, 
and then view your movie from the Test Results window.