My S40 began life as a RENTAL CAR, and 30k miles later, I purchased it. Why this car? Initially because of its value, reputation, style, & service competency at the dealership. I haven't had a single problem with my car. I commute 50 comfortable miles r/t daily, and get 30+mpg. I've never struggled to merge into fast moving traffic. I keep it clean, change the oil myself, and monitor fluid levels and tire pressure/wear. Volvo has higher value over time, and is safer than most other cars on the road. When I want 'performance' acceleration/handling/braking, I'll put on my helmet and leathers, and head for a track day on my superbike. My car is more than competent at what I expect from a car.
Smooth comfortable ride; instrumentation(quick and easy to read, easy on the eyes); Volvo's trademark tight turning radius; turbo engine(no performance decrease at higher altitudes, for example- passing on an uphill grade); ease of owner maintenance- fluids, light bulb replacement, fuses, etc.
Console and controls are bland, and could have a bit more style(my'06 S40 shows that Volvo has since addressed this issue). While a heavy car may improve snow traction with all-wheel drive, it certainly hinders traction on a car with front drive on anything but level ground. Better console storage.