Out of my solid-brass syrian, a generic egyptian, the MZ, and the collosus, i choose my MZ for everyday smoke due to its size (30" over the 26,28 and 40" of the others) and only. i've had the generic one for a few years and its still on good condition.
On rusting now, the green stuff that comes out of the hookah is normal for any brass hookah. It is not rust. Its copper from the brass reacting with water and Carbon dioxide. its totally harmless because it is trapped by water (has density more than 3g/cm3)