How Much Does it Cost to Install Countertops?
Artificial (quartz) is cheaper, more uniform, has fewer voids to collect dirt, and is almost as abrasion and chip resistant.
Granite is more expensive, stains and collects dirt a little easier as a rule, and is slighly more chip resistant as a rule.
For durability, I would not rate one over the other - barring a 250 lb guy hopping up on it and cracking it, either is likely to outlive you. Selection is typically based on appearance - quartz tends to be more uniform looking and does not always do a good job of simulating the veining and variations that natural stone has.
Now some of the man made stone counters rival the real granite and othe stones without the maintainence of stone. There are many of them out there and it is more a choice of looks than anything else. Corian is still a strong choice of tops today and one advantage is it can be repaired when scratched on site. If you don't mind the maintainence you can't beat the looks of real stone though unless you need a few pieces to make up the top as the graining may be hard to match up. I am impressed though at how realistic some of the man made products have become. It is more an issue of what brand are available in your area. Most all are made the same way with crushed stone and basically an epoxy binder used to make the sheets.