I wouldn't say either is better. HRPG doesn't easily let you say "I want to do this X times a week" for values of X other than 7, unless you want to specify the days in advance. I also think (with not especially high confidence) that "I'm about to fail at beeminder" is more motivating than "I'm about to lose health in HRPG" even if I don't have a pledge; but if I'm ahead, HRPG is better at motivating me to keep going. My HRPG has only occasionally got to the point where I was worried about dying, and then fear of failure was more motivating than normal, but usually I can coast.