Grab em whilst you can.
Amongst my citroen collection I have a Citroen xantia, yes its poorly at the moment but thats not its fault.

---Looks and interior---

It doesnt look like your average mundanoe and compared to the cars of today it still holds up well, different but not too different.
I personally prefer the mark 2 style with body coloured bumbers all round, it looks more modern than the series 1
With numbers dwindling you cant be too choosey, but there are plenty of scrappers on ebay and leather interiors and the like become available fairly frequently. Some even come with heated seats!

---Driving---
Being a proper Citroen it of course has hydraulic suspension and mine being non hydractive does not have any electricary to bugger it up. Therefore while not being as soft as a Cx it is still a lovely bump free ride that will make you wonder how you put up with tin sprung cars for so long! That said if you have a well maintained and working hydractive xantia it also rides very well.
To clarify lower specced xantias will be non-hydractive, And higher models will be hydractive, using a computer to determine how firm or soft the ride should be. This can be very handy when driving enthusiastically.
My 1.9td is manual and has very smooth gear changes, it feels very nippy and is responsive with little turbo lag.

---Reliability---
The 1.9td unit is a well tested Xud engine and was used since the late 80s. They will take much abuse and are exceedingly reliable provided you change the cambelt on time (guess how I know) being an interferance engine if the cam spaps its bye bye cylinder head time.
The hydraulic suspension is not as scary as some make out, in fact it is easy to maintain and any weak spots are well known and easily overcome. The main one to watch for is the strut tops as these rot and can cause the struts to punch a nice dent in the bonnet. If you are going to buy one and do nothing else, look above the front wheels and have a poke about. Also have a look underneath the car for a minute or so whilst its running to check for hydraulic leaks.
Another common rot spot is on a join on the upper sill area that can be seen when the rear doors are opened. However in my expereince the rust protection on Xantias is very good.

---Reasons to buy---
Fantastic amount of car for little outlay, yes C5s are getting cheap now, but Xantias in my opinion are just better! Especially if you buy a good one thats fully loaded with cruise/ air con etc. If you do buy one there are excellent forums with expert knowledge at hand to help and advise.