Not ever mastiff is good, but if you look around you can find EM that are capable of doing decent agility. In fact, just last week someone posted a video of an EM doing some agility. This is NOT my dog and I have nothing to do with this dog, but I do like it and I would love to see a solid Neapolitan do this. Of course, this isn't a nerve test or a temperament test...but it is a starting point. http://www.youtube.com/watch?v=8O-RyC7MxUo