being comfortable isnt an issue, its just they are so comfortable its easy to fall asleep while driving,
as for diesels, the D8 diesels arent that great, the 1.9td is bullet proof and goes for millions of miles, but is very noisy, very slow and not the most economical, the 2.1 is amazing, loads of torque, plenty of power, but again very noisy, but better fuel economy, but nowhere near as reliable as the 1.9, then comes the D9 HDis, this is what i have now, the 110 version, fuel economy is just amazing, ive had 68mpg out of it, about 300 miles to 20 litres

power is much better two, though not as good as the 2.1, as for noise, they can get quite bad at silly mileage, but mines on 167,000 and doesnt sound like a diesel at idle, but reliability can be a bit patchy, wiring problems and in-tank and high pressure fuel pumps can suffer with higher mileages and lack of maintainance, also injectors can give issues, which cost £350 each
but there are good ones and bad ones, its just luck i spose
the HDi 90 should be avoided as performance is on par with an iceberg