When Hal Higdon is the right pick
You want a plan with no decisions in it, one you print and stick on the fridge. And you already run the starting volume your Higdon plan assumes.
Then his templates work. They have been around for decades, and a lot of marathon finishers have used them.
When Run-R is the better fit
Your starting mileage or running days may not match a stock plan. Or your half marathon is an awkward 11 weeks away.
Or you have a recent race time you want paces built from. A plan built around you takes out the guesswork.
Run-R uses the same principles: a gradual build, mostly easy running, easier weeks and a taper. It sets them to your numbers and re-plans when a week goes wrong.
The honest bit
Both are free. Higdon has the longer history and books you can hold.
Run-R fits the plan to you, gives exact paces, and puts every session in your calendar.
If you cannot decide, compare a Run-R plan with the matching Higdon plan. Then run whichever you trust more.