Bugs :
1. The suit will regenerate it's own health if it takes a large amount of damage in one hit. This is because the code does not check to see if the damage taken will put the suit over the threshold for damage (1001). I fixed this for my own copy, and it works.
2. The suit will still absorb some damage even if the power level is depleted. (more than it would if it were armor)
3. If you die while taking a big hit, the suit parts will be destroyed. Again, this is because the code is not threshold checking.
4. NO Energy is used in SMP to increase the player's jump or speed. This is because the client never tells the server when speed running/jumping is on. (this might be bukkit only)
5. The client code obscures the true food level of the player. It should not affect food if platform is not simulating.
6. The client code applies the same speed boost while inside the nether, not factoring in that coordinates need to be divided by 8.
All these bugs are fixable, I have fixed most of them in my copy. For number 4, since I don't fully understand the client-server communications, I just made it so the client doesn't subtract energy to run/jump and it doesn't feed on the client if it is on server.
And of course the suit is ridiculously OP, but everyone knew that.
Also, the nano suit has the same "big hit" bugs as quantum. It can regenerate, and it can be destroyed on death.