Behavior-wise, the Cassin's finches appear to prefer platform or ground feeding with equal abandon, though they don't much care for the narrow tube finch feeders that the house finches happily balance on. Cassin's finches are also bolder and less skittish than many other of the backyard species currently enjoying my buffet, and they get along relatively well with other species, demonstrating less of the aggressive, territorial behavior some other birds exhibit.
There appears to be at least four pairs of Cassin's finches that have discovered my backyard sanctuary, and they're all welcome. According to my birding resources, the better the food supply the more that will attend, so in days to come there may be quite a flock present. The more the merrier!