I've used them for a year, and fell from them twice, the second time because a rubber shoe of the stilt broke apart, and strained a lot my knee. No broken bones, but it took a week to start cycling, then in 2 weeks I could walk almost normally, and it took whole 3 months to stop feeling the pain. I sold them after that.

Running in them is VERY hard, even if you do it properly (landing on straight legs, to not dampen the energy). You can run only at high power mode, like sprint, for 200-300 metres.