I've tried both and prefer the Varios.
On most day trips (probably 70% of my rides) I just use a small tail pack for carrying on-route essentials (couple of tools, puncture kit and mini compressor, map, bottle of water)
On overnight trips to hotels/b&b's then a small extra bag strapped to the rear seat with toothbrush, etc (absolute minimalist) - assuming no passenger
Longer trips, or with passenger. Varios. As everyone says, versatile and waterproof. I don't use inner bags preferring to carry the panniers into hotel (probably paranoia because I think someone may try and lever them open to see what's inside!)
As much of my riding is sans panniers, I really don't like the ugly scaffolding on the Alu panniers. Much preferring the clean lines without these frames.