No...
Don't go believing the land of Xantia is all peachy and shiny either. These still invent new
problems to confound and astound you and your bank balance too - they were STILL made
by Citroen after all!!
Mind, if you want a cheap '95 1.8 16v saloon I'm planning on getting rid of one shortly!!
As it happens, I've been through a migration to Xantiae and have come round full circle
again to Cx's (got to love'em really you REALLY DO) and good'ol Xm's!
I feel a lot of ground haS amptly been covered already here and echo my feelings too and
I'd always be the first to fall into the devil you know camp rather than plump for someone's
hand me down with it's attendant 'issues' and dodged bullets...
The brakes aren't an issue and as you've been ebaying already, you've no doubt seen there
are good prices to pay if GSF is still a tad expensive.
As far as the head gasket goes, it REALLY isn't a big job. Honest. Not massively expensive
either - for me the only real git in the job is the hacksawing of the downpipe bolts on the
collar where it meets the manifold - and that's IF you see the need to split it there - sometimes
the studs DO undo off the head!!

Generally from my experience an XU engine will need a
head gasket sometime in the same way a manual gearbox needs a clutch in it's lifetime!!
Just one of those things!
OH YES, I'VE SEEN AN XM SELF COMBUST WHEN THE FUEL PIPE PERISHED ON THE TOP OF
THE HEAD WHERE IT COMES OFF THE BULKHEAD. Well, that's what I think happened - the seat
of the fire was on the offside rear of the engine bay's bulkhead sending flames halfway up the
windscreen as I was doing 60 on a dual carriageway...
Twas either fuel or that 'I'll fix it tomorrow' leaking rocker cover gasket!!
Andrew