I previously owned a Mercedes C250 turbo diesel, and now a Volvo S40 standard.. Comparing the two cars I have noted differences.
The Merc had more power because it was turbo, but the Volvo has far more comfortable seats and is very quiet (it is a bit rough on bumpy roads).
It has excellent road holding, and is stable on the road, considering that my Merc had ASC and my Volvo doesn't have any assistance.
Also I find the interior build to be of a great luxury standard.. No rattles or moans.
I find my S40 to be reliable and hassle free, and very easy to drive..
Downside only being that the A pillars do restrict a bit of vision. And when you replace the standard radio tape with a CD frontloader, you notice the speakers don't have as much thump/ bass in them.
10/10. A great all around car. I love it, and would consider swapping it back for a Merc!!