A DEWcis a very intense beam coming from space and visible for about 5 seconds and the Rods of God look like a firey netorite trail and impacting the earth with such force as you get a major earthquake. The Rods of God can be seen on Radar since they are made out of titainium . The DEW you can not see.
The most fearful weapon would be a fusion weapon where hydrogen is exposed to such high magnetic fields the atoms nucleuses come together forming the next element up on the Periodic Table and on and on , in an unstoppable chain reaction. This is how the sun produces light and heat in an unstoppable fusion reaction.