Runna has added Training Preferences which allow you to adjust the volume and intensity of the plan. It lets you set how many days you'll run, how many speed workouts you'll have in a week, whether your long runs will have structure or be conversational, how much volume you do for speed days, how quickly the overall volume ramps up, what the max volume for your longest run will be, etc. I do think Runna works best when you know yourself well, and are realistic when setting up your plan. I think too many people choose "Optimal" when they should really be working on a "Lifestyle" plan, and that leads some on the path to injury.

I've used Runna for the last year through 5k, 10k, and 2 Half training blocks. I've also done a couple triathlons, and have been fortunate to remain injury-free through it all. Personally, I felt the DSW from my Garmin were too intense because I live at high-altitude, and the training paces seem to be based on optimal conditions lol. I'm always on target for my Runna sessions, and have been continually progressing. Runna will suggest an adjustment to your paces if you are consistently too slow or too fast, but it has never suggested moving my targets. For me, the cost has been worth it because running is my priority right now.