Had two diseasals (if you exclude two leased Rover diesels from 124 years ago) of my own and oddly both were Alfas.
I am not much a fan of the 1.9. I can only go from experience I had with mine and I did not like it. Two main issues were..
a) The uncanny ability I had to remove, clean and reattach the EGR quickly. People that know me, know I'm slow at just about everything else.
b) The ****ing in a biscuit tin noise. I really, really hated it.
I also had a 2.4, 159 which was ace, OK at idle it was obvious I burned crude but when nailed those 5 cylinders growled with pleasure, however recently it became poorly and my inadequacy and enthusiasm to fix the suspension made me sell it to a friend. He's not my friend now after I did that, but he did come to gloat last week.
He's fixed it and it goes like stink (the DPF was clogged too it seemed when I had it) and is as tight as a shark's arse at 50 fathoms.
I could be tempted into a bigger than 4-pots diesel but after my silky smooth German V6 I doubt it very much.
However I'd rather have a tractor than most milk floats.