I only do this for books, and I tried the cloud functionality for the first time last night. Bought a book on my iPhone 4, checked my iPad 2 this morning and the book was there. Not sure how the deleting part works, but I don't tend to delete books since they take up very little room anyway.
I don't want my music on the iPad, because I don't need it there, nor do I want to mirror all my apps. I use the phone and the tablet for completely different things, the only exception being my phone for spontaneous reading sessions where I don't have the iPad handy.