The Challenger sits between road and trail. The lugs are shallow and closely spaced under the middle of the foot and taller around the edges, which means it rolls along tarmac without complaint and still bites on gravel, hardpack and dry singletrack.
It is the shoe for runs that start at your front door and finish on a path. If most of your off-road running happens on fire roads, towpaths and forest tracks rather than in the mountains, it is a more sensible buy than a full trail shoe.
It is not enough shoe for technical ground. Those low lugs slide on wet rock and clay, and there is no rock plate to protect you when the trail turns sharp. For real mountain terrain, look for deeper teeth and more underfoot protection.