Mjolnir armor is amazing but it also requires the user to be a genetically and surgically enhanced super soldier of the highest order. It gives you armor that's nowhere near as good as T-51b, but it's also got strength, speed, cloaking, and a built-in AI-based supercomputer that can help you with whatever you need up to and including genetically engineering and manufacturing a cure to an alien virus.
The nanosuit is the best because anyone can put it on and use it.
