I came from petrol cars and bought the 2.4 as my first diesel. The driving style and shifting is a bit different and it took me a few weeks or even months to feel that I knew how to drive it properly/comfortably. I am always impressed by the power of the 2.4 (no mods on mine), especially the way it pulls me up in the mountains - it's like a freight train!
I drove the 2.2. once while the 2.4 was in the shop - and hated it. Sluggish, boring, short of power compared to the 2.4. Obviously I was comparing it to the 156 2.0 which I previously drove, and at the end of the day I was more than happy to turn in the keys and get back into the DERV. (now, what does that say about GM and the 159....)
Test drive both and you'll see. Diesel repairs are usually more expensive than fuel repairs, for example the cambelt change in the 5-cyldinder 2.4 is a "fun" expense as they need to lift out the whole engine (thus increasing costs...). Good luck.