I used to use it often with higher contrast slow films. Think pan-f, and rollei retro 80s. it did help lower contrast a little, but it did give a noticeable speed boost to the RR80 films. depending on the developer I was shooting it at 40-50, with beutler I could get 64 in normal contrast scene and 80 with lower. back in the day it gave nice sharp negs, easy to wet print when I used to do that.
As its easy to mix and obtain the chemicals, its always in my tool shed of developers if needed. Like the others have said, I mix up stock solutions and store them in brown glass jar for a few month, then dump if not needed. also, make sure to read the mixing directions carefully when searching the web on this developer. many people list mixing at 1:1:8, others 1+1+8, others 1:1:10, others 1+1+10
john