There seems to be a lot of people complaining about their Armour/Stealth/Power levels rising very slowly depending on what style they play, and not understanding exactly how they level, so I thought i'd clear things up.

Two elements dictate your mode XP distribution - kills and energy used. Energy used is a given. For the amount of time you expend energy in that mode you get a small amount of XP. Kills are the bigger contributor, which seems obvious, but i'll break it down further as it isn't that simple and is mainly what confuses people.

To get Stealth XP the game states you must kill someone within 8 seconds of you decloaking (although in reality it's more like 5). This overides the other two modes. That is important to remember.

If you want Armour XP but go into armour and get a kill within 5 seconds of decloaking, it's still a stealth kill. To get an Armour kill you must be in Armour mode and not have been cloaked in the immediate past. Taking damage expends Armour energy too, so for the small passive bonus, getting shot while it's active works better than just having it active.

Likewise to get a Power kill. You can't have recently cloaked and you can't be in Armour. Power goes up the slowest because most people will be in one of the other two modes when they kill someone, but it does go up passively every game simply due to it using the most energy due to sprinting and jumping.

Using the enhancement modules for each mode will help a lot with XP as you can stay in the modes longer and gain more passive XP per round, but again, it's kills that really drive the XP up. Using modules does not count towards the mode XP they're related to, so Air Stomp kills, despite being an Armour module, will count as Power Kills not Armour kills unless you're Armoured when you do it and have not recently decloaked.

Hope that helps.