Had my diesel JTD 15 months and 24K miles. Generally very pleased with it, a couple of points:
Don't believe the trip computer, the diesel consumption is much better than it says, try working it out for yourself. I'm told post 'facelift', i.e. Sept 92 on cars have a misprogrammed trip computer.
Be prepared for high tyre costs, I'm just about to replace the fronts for the 2nd time.
Yes, the engine it a bit rattly when cold, but that's hydraulic tappets for you - it's fine when warm.
You may get a few spurious error messages from the computer, my most common one is 'high humidity diesel filter' - which first happened on the way home from picking it up as new.
The handbrake on mine freezes up in -C weather - maybe I have a duff cable.
If the parcel shelf is struggle to get out, they have a fix, I think it's just smaller diameter rubbers, but it works well.
If you buy from a good Fiat dealer, the irritating little failures which seem to be a Fiat feature will be no problem - I find Tates in Hove, Sussex, are great. Anything at all wrong, they fix it under warranty.
Finally, nothing that looks like this should be as much fun to drive, maybe that accounts for the tyre wear - that and the 140 bhp + 'black box' optimiser. I've had two Espaces, Volvos, a Scenic, and driven most MPV's, this works best for me unless you have 6 people + luggage.
Max