Updated March 13 - 2014

Mecha Superman is one of the newest champions added to the game and is in my eyes one of the strongest tanks right now. His high amount of crowd control and Area of Effect damage makes him an excellent initiator who aside from absorbing damage, also deals a lot of damage around him.

Abilities

Leveling order:
Q>W>E>Passive and Ultimate whenever possible.

Actually upgrading either Q or W first doesn't really matter, i just prefer upgrading Q first because it's a lot easier to land on enemies.
He has quite a few mechanics that might be a little difficult to learn at first. Your W, E and Ultimate all create small environmental objects which can be interacted with just like the normal objects (yes, you can use teleport, consume and superstrenght on them).
Using his Q on small environmental objects (not including cars) will destroy them and silence nearby enemies for 1 sec.
Using his W on small environmental objects will destroy them and knock up nearby enemies for 1 sec.
This is already written in his champion description, but i wanted to include it to make it more clear how it worked.

Stolen Powers

I prefer using Mecha Superman's Consume and Catwoman's Teleport. You are not so strong early game, so the bonus sustain from consume might become quite handy at some point And if you're winning lane and are pushing it to enemy tower, you can go solo the EMP buff on your own thanks to the consume. I don't recommend going solo EMP until at least lvl 4, the dmg you take won't be worth it until there.
The reason why i use Mecha Superman's Consume is because lategame the heal will be really powerful.

Catwoman's Teleport is a very normal pick of stolen power as a solo laner. The less time you're away from lane the better. Quite simple