I've owned a 2003 non-turbo S60 since new. The S60 is basically the 850 and S70 updated (and corrected) and is generally more reliable than either. Consumer Reports rates the 2004 as above average in reliability with only minor problems in the automatic transmission. My '03 has a manual transmission, so I can't corroborate CR. However, they noted suspension problems for the '03 (but not the '04). No big troubles after 97,500 miles of Boston area potholes, but I've had to replace some suspension parts that I'd never heard of, and some I had. It's never a big thing but rather an annoying repair every now and then. It is not a Honda in that regard. This, my seventh year, is so far a very inexpensive one, but I expect to make up for it with the 105K servicing.

Seats are extremely comfortable especially on a long trip; all the electricals work perfectly as the day they were new; all in all the car is a joy to own, look at, and drive. Note that the manual transmission model feels a bit quicker than the automatic.

Flush the oil and put in synthetic. The filter is inside a cannister, you cannot use a leftover Mann filter.
Then, drive it. It doesn't have as much room as your other Volvos but is almost as easy to park as the 240.

Klaus
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The more I learn, the more I forget. So why learn?