They are as reliable as any other European car.I would go for a 1.9JTDM 16v, you will be astonished by the torque and the low fuel consumption, probably better than 45mpg. Highish mileage cars as long as they have a good service history are probably better, and better value, than low mileage of the same age, which have probably just done short journeys.
Make sure the cam belt has been changed and the water pump at the same time. Expect some clonks from the suspension, the bushes are fairly soft, but they're not expensive to replace.
Don't be put off by uninformed bias. They are great cars, and I've never seen a rusty one.
My wife's has done 66k miles and is just like new. My GT diesel has done 78k, also like new.