Never seen the Proto one, but my NXe Executive is huge. I fit in two guns, two tanks, two hoppers, two masks, barrel kit, harness, 5 pods, jersey, pants, tools, cleats, gloves, etc. There's not much more room to spare though, but that's plenty.
I like it because there are separate sections for each portion of your gear so they don't clash. However, it's just like a suitcase with dividers in it.