Community feeding can be benefical if done correctly, done incorrectly it can be a disaster.
I use communal feeding when feeding selected hives, if I've feeding them all there is no reason for a communal feeder as the bees should have enough "at their door step" to prevent them from robbing.
When only feeding a few hives, the hives that are not being feed may begin robbing to get at the nectar source within the weaker hives it is then that I use a communal feeder.
Feeding communinally must be approached the same way as feeding the individual hive, the access must be limited, the source replenished as often as necesary (checked daily), and mimicing nature will decrease robing issued. By limited access I don't mean what/who's it limited to but rather limited on how many bees can feed at a time. To that end I use a 1 gallon paint can placed in either an orchard, a vegitable garden, or a flower garden. I place it on a board, upside down, with spacers so the bees can access it from underneath. I put about 18-24 holes in the lid for the bees to pull nectar from.
When I feed communally you can see the bees stacking up for their turn at the feeder and the only fighting I have noticed, of any note, is that of hornets, wasps, or yellow jackets trying to break into the line.