Moats will slow down a Feudal Age rush just a little, but don't expect that your watery barriers can replace actual defenses. Although they can't be destroyed, moats are also narrow enough that ranged units can fire right over them. We have experimented with some defensive maps before, such as Fortress and Arena, that begin with walls. Moats takes an entirely new approach to dealing with early attacks. Each player's town is surrounded by a narrow body of water with several land bridges for access.
Early raiders might have trouble making it into your town, but one long-range archers and siege weapons come on the field, you better be prepared to fight back. Also be aware that most of the forests are going to be outside of your moat, so you are going to have leave the protection of your starting area to collect lumber. There are also a fair number of deer on this map that might encourage you to venture outside your town. Except for the moats, there is no water and no fish. Don't even bother building a Dock.
For the would-be map editors out there, Moats represents some of the oddball things you can do with map scripting. To create this map, I actually made the base terrain water, and then filled in everything but the moat with land. Setting spacing to other terrain types equal to 1, left just the moats present, and then I used connections to allow players to leave their own towns.