Something to think about ~ these groups are really different in many fundamental ways. But, the possibilities don't stop there ~ at the moment efforts are underway by experts in the field to demonstrate that archaeotes, procaryotes, and eucaryotesall arise out of viruses, and not the other way around.
Bet some of you had no idea there's dispute on the matter eh?!
Given the probability that the tools necessary for life arise directly out of perturbations in space/time, life elsewhere should resemble one or more of the types of life we have here.
In fact, it's even money that folks won't be able to tell the difference (at the molecular level).