Answer: A nice patio properly constructed and using polymeric sand for the gaps will work great. Weeds coming up thru the edges of the stones may be the issue in the long run. Just add more polymeric sand every 3 or 4 years as needed. However decks require a lot of maintenance if you want them to last at least 20 years. Yes, maybe decks do have a feeling of warmth. But, are you building a deck just to have an expensive looking deck or do you want a nice place to hangout with friends and family. If you live in a neighbourhood with small lots sitting up 3 or 4 feet high on a deck may not give you the privacy you would want. However sitting level with the ground may give you more privacy.
Patio will also not give any neighbourhood critters a new nesting place, as under a deck would. Also, if you have any basement windows in the back of your house they may get blocked. Costs for either will be almost the same.