This is a very good cafetiere.
The capacity: It can certainly fill 8 espresso cups, the little ones. If you want to go for standard mugs, or breakfast cups, you'll have just over 2 units of either mug or cup. The choice is yours!
It is very unlikely the glass can brake because of a temperature shock, as it is special glass for this kind of circumstances. This is different if the glass is brutally manipulated or if there are strong strikes from within when spooning the coffee in the (just under)boiling water before waiting for 3 minutes and pressing.
When pressing the coffee, do not rush to pour it and wait a few minutes for the coffee to set and avoid the "mud" at the bottom of the cup.
Another way to avoid that "mud" is to grind the beans yourself on a coarse setting, so that the ground is not too fine. The ordinary ground coffee tends to be too fine for cafetiere (better for filter).
If not in a rush to drink the whole cafetiere, and worried about the coffee cooling, you can always use a teapot cover. It works really well to keep the coffee warm. Another way is to use a camping thermos bottle.