After looking over the posts, here's what I can gather about the various technologies:
Standard non-Powered Armor:
Would naturally be cheaper and easier to manufacture/maintain than powered armor due to not needing mechanical parts to it. Will almost always have less protection than powered armor due to the wearer having to carry all the armor on it. However, it could be standard equipment for all personal even when they are not in actual battlefields... kind of like how the Imperial Stormtroopers can wear their armor on ships so they can act in the event someone makes it into the base.
Powered Armor:
More expensive than standard armor but should always provide better protection due to the suit being able to support its own weight, thus you can put more armor on a soldier without weighing them down. At the very least, a suit of Power Armor could just be a powered exoskeleton with extra layers of the standard armor material covering it. Like the Powered part would just be a frame that the soldier wears and then they put on an extra thick Keval or
Dragon Skin or a StormTrooper could wear a powered exoskeleton and then have much larger and thicker sections of Stormtrooper armor placed over it which they couldn't normally carry. Or you could give them stuff like tank armor if you really need to.
Basically, the Powered part is just there to let soldiers carry more equipment or wear more armor.
Vehicles:
Vehicles are a completely different thing than armor or powered armor, they are built to do their job and may have a human pilot inside. They should always be able to have better armor than a human since the frame is build to support the armor and can carry better weapons for the same reason. If there is any sort of super matieral to make armor with that it can be used make vehicle armor just as easily if not moreso than human armor.
Besides, if you have an armored tank or an armored car then it can be made with better armor than powered armor, so just have the pilot wear standard armor when inside it.
Dalek-style vehicles:
Probably better described as One-Man Urban Combat Vehicles or something similar. Its quite possible that they could be built with protective armor superior to Powered Armor, but their size would make them awkward for use in actual combat. They would best be described as armored wheelchairs, if they are small enough to fit in through doorways or places that a normal human could fit then their wheels or treads would have trouble moving over rough terrain. That, and they would have to be larger than a person or even a person in Powered Armor.
Dalek-style vehicles would best be suited for small creatures or individuals who can't move on their own and find Power Armor difficult. Its doubtful they would be used for front-line combat since in open areas you could just use a larger vehicle like a car or tank, and in urban environments then human mobility would be a must. They could be used to house non-combatants or people who won't be fighting directly... like a tactician is inside it and commands unmanned drones via short-range radio or something or in case they need to evacuate civilians and just plop them into the vehicle and it drives back to base with them inside.
Unmanned Drones:
Unmanned Drones can be build faster than human soldiers and can be designed to be tougher, smarter, faster, and stronger than soldiers as well. They could be in any shape or size ranging from small tank-like things to mouse sized ones that carry bombs, or flying combat vehicles. If the army can build Power Armor or build any sort of vehicle than that same device could be converted into an unmanned Drone with the addition of combat AI.
Thus, you could have dozens of suits of Power Armor and decide to either fill them with a soldier or plop a computer into it and have it fight as an unmanned drone... same with vehicles and such.
However, while robots are superior in speed, calculations, and other physical skills then they can only think in ways they were programmed to do (or you could make them self-aware which can result in other problems). With unmanned drones there would be the risk that a software bug or tampering would result in them shooting someone you don't want them to shoot or overlooking things that they weren't programmed to recognize.
So, unmanned drones could be designed to search out targets and relay their findings back to a controller who gives them the authorization to attack. The controller could be thousands of miles away communicating via satellites, or they could be right there in the squad in armor giving them voice commands.
Squads of soldiers could go into battle with several robotic drones tagging along to serve as a force multiplier, they send in the robots to scout out dangerous areas or to stand guard, or carry out suicide attacks if necessary. The soldiers would be in control and be nearby to perform tasks the robots cannot and to ID which targets the robots can shoot at if necessary.
A robot with vision superior to a human could enter a situation and spot a someone on a roof several hundred yards away, it could be an enemy sniper, a frightened civilian, or one of the teams allies. The robot tells its human operator what it found and the operator tells it what to do.
And, in the event that a combat robot is cut off from its human operator then it could run commands depending on its instructions. Maybe it heads back and tries to re-establish combat or keeps going and if it runs into anyone it thinks is a threat then it yells "Drop your weapon and get on the ground with your hands on your head, NOW! You have three seconds or I will OPEN FIRE!." Even if the AI isn't advanced enough to identify human faces or other things then I'm pretty sure it would be able to determine that a person laying on the ground with their hands on their head isn't a threat.
So unmanned drones or combat robots should be much more effective at fighting then soldiers as long as the tech is in place. However, a smart military would have safeguards in place to make sure the robots don't kill the wrong people and that they aren't crippled if unforeseen events interfere with the mission. Plus, a robot that is just a gun turret on wheels is probably less likely to start a robot rebellion than a fully humanoid one. At the very least, if the robot turret has a limited amount of ammo and needs a human operator to replace its magazine then its rebellion shouldn't last that long... particularly if its off-switch is located near the ammo feed or you have to disable the gun before you can reload it.
Fry: No! They did it! They blew it up! And then the apes blew up their society too. How could this happen? And then the birds took over and ruined their society. And then the cows. And then... I don't know, is that a slug, maybe? Noooo!
Futurama: The Late Philip J. Fry