Under ideal conditions, flat roads, tracks etc. they would work fine.....long grass, sloppy mud, soft sand, brambles/briers not so sure about. The fact that it suggests twice your normal comfortable load doesn't sound so clever when it comes to having to take it on and off regularly to climb stiles, fences, cross ditches etc. I know how much easier a trolly or barrow makes it when carrying fishing gear....at least it makes it easier until it doesn't and it doesn't a lot more often than the adverts and salesmen would have you believe.
D.B.