"Map dependent." Yes, that describes Palmy to a "T." While only a fool or a supremely cocky individual would deliberately take them in a 1v1, they CAN be of service to a 3-man team (I wouldn't even dare in a 2v2), IF, and only if, there are abundant resources for them, including a readily-available food source. Palmy does not have the luxury do scout for food too long, although you do have a tiny window of opportunity, since there's going to be a lag in early vill production no matter how well you start.
Being in the pocket is almost a must - which, of course, you have no control over. A palmy on the outside, especially one faced with a superior opponent or fast civ, needs early support from the pocket player, and must also commit his precious villies on walling.
Still, with the right conditions, and ample early protection, the Palmy strength will certainly be felt - in giving plenty of food from those amazing fish boats, and all that wood, etc.... Of course, this is not a military marvel, as none of their units (save camels) has any particular benefit. Still, they can lend them, and later, scythes, to any battlefront, and still have a robust economy.
Having said that, when the random gods curse me with Palmy, I curse back. Loud and long.