I use FP4+ and develop in either HC-110 dil h, Tetenal ultrafin 1+20, or Ultrafin Plus 1+9. With all three chemicals the results are quite nice, and given the versatility and shelf life of Ultrafin Plus, worth the effort. 1 liter of Ultrafin plus 1+9 will do 12 rolls, or 48 sheets of 4x5. I use it until about 8 rolls or 32 sheets. At 1+9, I get 11 liters working per liter concentrate. My times for developing were running 12-13 minutes.
The Ultrafin Plus is one of the best.