We had one of those for my son when he was a baby, Denis, and we've got a small one for our daughter, but it always made me nervous. My husband used it with our son, but I was always worried that I'd slip and fall, even with hiking sticks. I keep in with the baby's BOB, but I think I'm going to give it a go on the paved trail around here. It'll be a good workout, me thinks.
One thing about the baby, she keeps me on safer ground. If she can't get there in her stroller, she doesn't go. That said, when talked with the Ontario Volunteer Emergency Response Team's Canine Unit on the weekend, and they told us the story of a woman and her baby and toddler who got stuck a the mucky lake bottom at the camp we stayed in last weekend, and triggered a SAR operation because she was lost to boot and couldn't tell them where they were in the park so they could come dig them out.