If you had to choose one or the other for your home, which one would you prefer? Do you currently have either a deck or a patio, or both possibly? Decks usually add to the value of a home and give more options for multi-level houses. Patios are simpler, but can be added to rather easily, more so than a deck. Decks also carry more work with it such as staining and water-proofing. The house I am purchasing as a deck already in the back which is attached to the top story of the house. It also has a gazebo on it since it faces the setting sun, and there are not many developed trees around.
The house I current live in has both a patio as well as a deck. The Patio is much easier to maintain honestly but I find that it is also much more prone to clutter. It is too easy for me to pile things up on the patio than the deck. My deck does not attach to my house at all. There is a concrete walkway from the patio to the deck but nothing joining. The deck is attached actually to the pool. I feel much more relaxed sitting on the deck as it is much more open to the rest of the yard. Decks in my area are much less common than patios are so I feel it is a greater addition to my house.