Phew! Glad that's out in the open.
On the up side, the Xantia is much better screwed together than the BX, and is much quieter on the road. On the down side this makes it much heavier, slower, and thirstier.
There are a few design quirks that will probably come to haunt you. I will let them surprise you though for now.
I've nearly covered more miles in Xantia TDs now than BX TDs. Still rather have a BX though. If that 42k estate had been within 100 miles it'd be parked on my drive now