I use D23 diluted 1:1 as my standard developer for TMAX-100. I get good results and good highlight control. I use it for both 120 roll and sheet film.
I usually rotary process in my Jobo 20 C for 12minutes or small tank for 14 minutes.
I have also used it with Agfapan APX-100 with equally good results.
There are a number of adantages of using D-23, it is cheap, can be made up when needed or you can make slight variations, like adding 2 grams of borax to make D76H, or use it as a divided developer.
A good discussion on D23 can be found at http://www.heylloyd.com/technicl/D23.html