Do not build a deck over a 40 year old cracked slab unless you bust out the creet where the piers are going. Do not install pavers on a 40 year old cracked slab.

Stamped concrete is cool looking stuff so is a S American lumber deck. Both would require some good ol JackHammer work. J.

Totally depends on preference. Pros & cons to both and nothing is totally maintenance free, although some things may require more maintenance than others.

In our Upstate NY climate, everything takes a beating - regardless of selected product.

Long story short, I will never have another deck nor do I prefer poured concrete. Decks take too much of my time and money for maintenance (even composite) and I just don't care for the stamped concrete.

In our climate, poured concrete shifts as do pavers.

Pavers (or natural rock) are much more forgiving to shifting than concrete which generally (not always) eventually splits & heaves (even slightly) around here. Pavers shifting are easier to remedy than poured concrete should you desire to do so.

I spend a total of 30-60 minutes a year maintaining the paver patio which includes weekly sweeping and minor weed killing in the cracks. Zero cost in supplies - just time. Probably not much more in maintenance for a poured patio either.

The deck we used to have required washing, water repellent treatment (staining if preferred), tightening screws/bolts that came loosened up over time and occasionally replaced pieces of floorboards that became warped or split, parts of the skirting (should you choose to have one), and spindles on railings which became loose over time from bumping, leaning etc...

The patio allows us to be ground level with shrubs & flowers which we used to only see from above on the deck.

Fast growing plantings around the patio can screen things out pretty quickly as well, should the need be there. When your up on a raised platform like a deck, sometimes it can be more challenging unless you integrate a wooden screen into the design (which requires maintenance like the rest of the deck - more time & money).

Regardless, I would remove the existing slab before I'd do anything.

Should you go with a deck, the footings will need to be dug into the ground which will require removal of the concrete.

Patios (poured, paver or stone) are only as good as the base they are built on and the current slab would need to come out to do build your new base.

Only opinions and preference but it's good to consider all options that you are to make the best decision for you.

Thanks, I appreciate the input. Dontknow - I am in upstate NY also, so your points about maintenance would definitely affect me. I'm going to look into pavers.

Both of the people who have come to look so far have recommended leaving the existing slab in place and building over it. They said that it's in good structural shape (despite the surface cracks that bother me from a cosmetic perspective) and would make a good base for a paver or natural stone patio. One of them did a flagstone patio for my neighbor over an existing (old) concrete slab. Does that sound totally out of line to those of you who are reading?

I've read and heard of paver / stone patios being laid over an existing concrete slab. If the slab is in good shape, it may be fine but it'll raise the level of what goes down on top of it and may need to "step up" onto the end product.

Do yourself a favor if you are shopping installers for pavers, look for an ICPI Certified Paver Installer for at least one opinion/estimate.

Here's a link that might help if you are not familiar with ICPI.
http://www.icpi.org/homeowners/

I'm not affiliated in any way with any of this.

Although still not guaranteed to have it done correctly, I used it as a starting point for beginning our installer search figuring it's cheaper to have it done right the first time than to undo / redo.

Good luck!