The TDCIs are not bad as long as you use decent quality fuel, ideally from a station that has had new or recent fuel tanks. I've seen a car last only 30k with injector problems caused by running on supermarket fuel.

You can get more power and efficiency out of the TDCI but you probably wouldn't notice the difference between the 2.

The TDDI can suffer injector issues but it's rare. Usual signs is loss of power and slightly uneven running with no fault codes in the ECU. Rare but it does happen.

We maintain a TDDI Transit which has recently clocked over 400k miles, still on the original pump/injectors. It's had a dual mass and a starter though.