Artillery towers have a property which none of the other towers have; It's my favorite because it's unique in that sense. The artillery explosions can harm cave spiders if visible ground mobs are nearby, and the same can be said for flying mobs. It's the only tower with that property, aside from the castle guard, but it doesn't last through Armageddon mode. No mobs are truthfully immune to it.
I'll list one mob that's immune to each of the other towers below:
Archer towers can't target cave spiders at all.
Mage towers can't target witches.
Ice towers don't appear to slow down giants at all, and they don't damage.
Poison towers can't poison air mobs. (If you're not sure, ask yourself how many times you've seen bubbles coming from air mobs even with ground mobs underneath)
Zeus towers can't target cave spiders or do damage to them at all.
Quake towers don't target air mobs, nor can they affect them whatsoever.
Sorcerer towers can't target or damage air mobs.
Turret towers can't target cave spiders.
Necromancer towers can't damage any air mobs, but they can chase after them.
Leach towers can't target cave spiders, and the shock-wave doesn't hit them at all.
Castle guards can't damage any mobs at all after Armageddon mode begins.
Every tower except for turret towers have a purpose for me, and I use them all except for turret towers. However, I like artillery towers for all of their properties, including the unique property that it has.
