Sorry, I forgot to respond to Howard's comment. My red blood cells are attacked by my red wine.(posted 8221 days ago)I can't say much because when you say "incredibly" fine grained, I don't know how fine you mean. I once exposed HP5+ at EI 100 and processed in HC-110 1+11 but the resulting image was still as grainy as in ID-11 1+1, and much more grainy as in D-76Ad 1+1. People seem to agree that EKC silently changed their formula for HC-110 at least once, some even proceed to say a few times, in the past. HC-110 could be finer grain developer before, but because I started photography about the time Panatomic-X discontinued, I don't have a real feeling for the older HC-110.
It has been my experience that with HC-110 lower concentration than dilution B is favorable in terms of apparent grain, highlight retention and tonality with all of a few films I tried. However, HC-110 is an incredibly low concentration formula, and HP5+ is a very chemically greedy film, so I gave up on this combination a while ago. With films like TMX and APX25, HC-110 at half concentration of dil B works pretty well, though with TMX you get metallic look.
If you look at my home page, my chicken soup for HP5+ is D-76 like ascorbic acid formula at 1+1, and my gumbo soup for TMX is something like Ilfosol-S but without hydroquinone but with some more buffering effect. Going back to your original question, I think vitamin C formulae can strike a better balance between various qualities compared to MQ, and in particular I think there is no penalty (only some benefit) to move from D-76 1+1 to its ascorbic acid counterpart except it costs a nickel more and you can't buy it from your local stores... If you live near Boston, you can buy from me, of course, but it would be a lot cheaper to mix yourself :-)