The Xsara is one of the most smooth and comfortable modern diesel saloons I have come across.
Visibility is average (the door pillars are quite big, but no more so on most of its competitors) although I can't see any of the 4 corners which can be an issue parking. Seats are fairly standard, adjustable as you would expect. The interior plastics are pretty basic but do the job. The rear seat is split 2/3-1/3 so there are various options for folding them down. They go down almost but not quite flat. The boot (strictly a hatchback as only a parcel shelf separates it from the main part of the car) is very spacious for the size of car.
The ride is smooth & easy and it will accelerate even from 50mph in top (5th) gear. It will wheel spin if you really put your foot down in low gear but has never done so accidentally. Even in the recent heavy snow it has handled very well.
In an average week (mainly short trips with the occasional motorway blast) I'm getting 45mpg so although it does cost £50 to fill the tank I get plenty of miles from that. Parts are fairly expensive, especially from the dealer. Tyres generally fairly low profile which pushes the cost up on those too. But (touch wood) it's fairly reliable so the cost of parts shouldn't be an issue very often.