Well, the D5 is faster, smoother and more economical.

The D5 is not known for its problems - if you run a car like this it will never be the cheapest to run (if you want cheap buy a year old Aygo for the same money). On the whole it is pretty robust.

OK, so over the long term you might need an injector, intercooler or engine mount but you can't expect to run any relatively expensive car without some maintenance.

The last of the old shape have less issues than the early new shapes but you should be able to find a 03 ish D5 with 100-120k in your budget by which time most issues had been addressed.

I have a 2003 D5 bought a couple of years ago. Needs cambelt at 90k and check the pads - discs and tyres carefully. the car has been v good and could swallow a baby elephant in the back, with the rear seats down baby's mother might just squeeze in. Forgot to say the injectors ain't cheap so make sure they are ok or get one of those warranties.