I have had excellent results with this combo.

Tri-X in 4X5 sheets is my favorite film to date, and I was getting good results with a D76 1:1 clone, but the sheets developed in DD-X at the recommended 1:4 dilution seem to have sharper edges to my eye.

However Ilford does advocate one-shot use, and my experience is that it will begin to show signs of exaustion at approx. the predicted capacity (unlike some other developer capacity statements that I have found to be conservative). I let 24 sheets (I have a habit of working in groups of 12 because I sometimes use a daylight tank) go through 1 liter before tossing it out, but I wouldn't push it any further that that.

I was exposing at ASA 200 and tray-developing with constant shuffle for 6 min. (Yes, I can usually successfully shuffle 12 at a time in trays )

This combo has yielded some of my best negs to date, but as they say around here... "your mileage may vary" !