Compared to D-76, this chart indicates that HC-110 (dilution B) produces:
o Slightly less shadow detail or true film speed;
o Slightly finer grain;
o Slightly lower acutance.
Apparently, HC-110 has somewhat more solvent action than D-76, but less than Xtol.
Opinions differ about the effect of HC-110 on grain. Some photographers report coarser grain than with D-76; others report finer grain. This is probably a function of dilution and agitation.
Opinions also differ regarding acutance, since many photographers report that HC-110 produces high acutance, especially at high dilutions. This is a function of solvent action, which is reduced by diluting the developer.
The above quote is from the Covington HC-110 website. The unitalicized portion is directly from Kodak literature.
It appears that one's opinion seems to depend on the dilution used. I have always been very happy with the results that I get with HC-110.