HC110 is an excellent choice for HP-5 and is the combination I often use. It's also excellent with Acros and Neopan if you have any. I'm also very fond of it with Delta 100 & 400.
As mentioned it's very versatile and the concentrate keeps for very long periods.
I've tried the Freestyle version and when freshly opened it's comparable to Kodak HC110 but it unfortunately oxidizes in a few weeks in concentrated form. For that reason I quit using it.
Ilford makes an equivalent of HC 110 called HC. Film responds identically when developed in it when compared to HC110. The downside is it's much more expensive than HC110.
I still recommend doing as in a previous post. Mix your stock then divide into smaller GLASS, not plastic, bottles. If not totally filled use Bloxygen or Wine Preserver to displace the air. Another solution ive heard people use is to drop marbles into the bottle to raise the liquid level and displace the air.
Since youve used D76 and you like it I wouldn't change. Changing requires dialing in speed, agitation, times and ISO all over again. In addition HC110, Rodinal, DDX, D76 or any other developer will produce different negatives. Pick a film and use 6 different developers and you'll get 6 different looking and printing negatives.