Edited out the whining at the start of my post
You can't straight up compare them like that. They are used completely differently, and fit into the doctrines very differently. They both pop out of buildings, but beyond that you shouldn't be using them the same. Storms sneak, decap and raid, then retreat to be refitted as useful infantry. Partisans ambush and are expended.
Storms also got buffed, and in a way that is meant to encourage their use as more than a quick shock.
The thing is, Storms are not good at what they are supposed to do, decapping and raid, because of their
basic weapon and upgrading time+cost. And Partisans are not for ambush, they're for surprise attack for team weapons. Did you even understand about them properly?
Retreating to be refitted as useful infantry? Calling MP and upgrading cost is too much...
What's better to use storms instead of pzgrens(average 1~2 produced for 1vs1 game unit)??