Volvo Dealership is about to replace my entire engine under warranty...question is, should I keep the car?

A little more information: we brought it into the dealership because it was going through oil faster than expected and we bought an extended warranty so everything is covered. They have had the car over a week in the shop, and  shared nothing with us expect that they had run some diagnostics and were waiting to hear back from Volvo corporate. They just let us know that they received authorization from Volvo central to replace the entire engine.

We bought under a year ago (used 2008 Volvo XC70) but now I am less confident of my purchase. What kind of damage may have been done to other parts of the car?

My question is: Should I ask for a different car or equal or greater value, or be happy that I have a new engine in my used car?

Thanks very much for your feedback and opinions.