My wife put both of these sets in my stocking this year. The robots and ninjas are close to classic 1/32 toy soldier size. Maybe slightly smaller. The purple monsters vs. military are smaller. The soldiers are probably a little bigger than 40mm. The monsters, particularly the bird guys could do double duty as very tall avian people. But most of them are probably too big for standard war gaming. I will take comparison pics tomorrow as I am away from home.
Oh and I agree these troops are better than the Mars attacks ones, and the plastic is about the same level of crappiness/bendiness. 😜
Edit: Comparison pics: