Raze is way better I think. The only thing witch is better on armor mayhem is the way you can buy armor. I hate the fact that you have to by guns also Raze has better graphics, beter gameplay and better story/missions but I do like the stealing computer date game mode on armor mayhem.
I'm going to go with Raze. The characters in Armor Mayhem are just too small and you can't get anything to re-charge your shields. And you can't carry more than two weapons in Armor Mayhem, you can carry up to ten in Raze and seven in Raze 2. The original Raze has better character customization.
But Armor Mayhem as some things that Raze lacks. I like to actually unlock the weapons and armor I use (whether through achievements or buying, I don't care). It gives you something to save up for and look forward to. And when you finally unlock it, you feel rewarded.
And Armor Mayhem also has a map editor. I love playing on maps I've created and submitted. I have yet to try out AM's map editor because I'm not good at creating things, but it's still fun to play on a map that you made. And when other people vote on it, it helps to show you what you can improve on.
So, I prefer Raze but if the sequel had those two things (I know you have to unlock weapons in the second one), it would be even better.
RAZE is much better. I have found was to just cheat the AI and get nearly all the kills and nearly no deaths in the quick match mode in armor mayhem. All you have to do is find a long flat area at the edge of the screen with health nearby and stand there, most of the enemies will come in facing away from you shooting at another enemy. All you have to do is shoot strait forward and kill them both. And if you get low on health just run to the nearest health station. you win every match. If its teams just go to the same place and command your team to stand a foot in front of you, you'll never die. Also in data collection games just go strait to the nearest enemy base steal the data and run back, then repeat. The enemies will be to busy fighting to stop you.