Dino Esposito, in his last post on his weblog, said that when using the PostBackUrl property to do a cross-page posting, a normal postback is made to run any server side code registered with the original page, then a cross-page call is made to reach the next page. So what's the difference between a cross-page posting and doing a normal postback and using a Response.Redirect to move to the next page?
In my opinion, the only difference is when passing data from one page to another. Using cross-page posting, the destination page will have access to the controls and their values of the first page. But using Response.Redirect, passing values from one page to another would be through querystrings or sessions or some other way.