I've put about 140 hours on my Ground Shark, and I'm on the fence as to whether I'll keep it or try something else. The first problem was the pressure gauge breaking, and I plugged the hose and continued to work...not really a big deal. The second problem has been the bolts holding the blades shearing off, and I've probably replaced all of them at least once. The third problem has been keeping the stump grinding teeth tight and from coming out, and there are no rocks or concrete where I've worked. For just "underbrushing", the GS is fine, but in my opinion, it's not heavy duty enough for "brush clearing". For $10k, I expected more.