Hi xmannix

Both sentences are possible and correct. I tried to figure out which version I would use and I think I prefere the one with ist in the middle - it just has a better flow to it. German is sometimes rather flexible with word order. Maybe an expert can deliver a better explanation?

Both sentences are correct. You can say "Warum LeBron James besser ist als Michael Jordan." and "Warum LeBron James besser als Michael Jordan ist."

But like Cythra, I would more likely use "ist" after the comparison and I guess it is more common here in Germany.

I thought I might just add something from a different perspective, because Cythra and MadBaChi really knocked this one out of the park already.

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There is a flexibility in German for splitting a single clause into a dependent and independent clause. Two verbs I see this done with a lot are „aufhören“ and „aussehen“. Both of these are separable verbs and therefore, when they are the conjugated verb in a main clause their respective prefixes are sent to the very end of the clause. Here are two examples:

„Hör mit diesem Unsinn auf.“

„Du siehst wie ein neuer Mann aus.“

Which, when you've gotten used to the idea of separable verbs, is perfectly fine. However, as I've come to learn with my increasing exposure to the German language, what you are actually more likely to hear/see is actually:

„Hör auf mit diesem Unsinn.“

„Du siehst aus wie ein neuer Mann.“

Which I have learned to rationalise as basically splitting the one clause into two clauses; an independent and dependent clause. So in my mind it would technically be more correct to write:

„Hör auf, mit diesem Unsinn."

„Du siehst aus, wie ein neuer Mann.“

Though, please note that this is only "more correct" in my warped view of the German language.

So, in my head, what's going on with your question is:

„Warum LeBron James besser ist, als Michael Jordan.“

And therefore, what you've got to look for in cases like this is something that can act like a conjunction; with „aussehen“ it is always „wie“ (as far as I know) - meaning you would never get anything like:

„Du siehst aus gut.“ Nope

„Du siehst gut aus.“ Tick

And with „aufhören“ I think „mit“ plays a similar role, though, in fairness, I rarely ever hear anything between „hör“ and „auf“.

In this case „als“ is the sort of conjunction that is allowing „ist“ to sit there in the middle.

Sorry for the novel, hope I could help.