I'm also a motorcycle guy

That said, I'll have to trow in a "that depends". Keeping in mind that 4x4 and motorcycle are totally different applications. I'll trow out the pro's and con's and see what you think is best for you...
Lighter Wheel:
All these pro's are for "at speed" (driving on the street). When traveling slow (like when offraoding), a few pounds of rotational weight doesn't matter. On the street, you'll see gas savings, improved breaking, improved accelleration, and less unsprung weight = your suspension will behave better.
Cons: Won't take the same abuse when offroading. Steel is MUCH stronger, and can take punishment from scrapes and dings.
So, if your Zuk is a daily driver, aluminum is good. If you're wanting offroad reliability - keep the steel wheels.
~J~