Between a 2 way and a three way set up?

 

2 way setups only have a midwoofer and a tweeter. So you have your mid playing from like 80-2500 hz (just examples of numbers) and your tweeter playing from 2500hz on up.

3 way setups have a midbass speaker, a midrange speaker, and a tweeter.
Your midbass will play like 70-400 hz, your midrange from like 400 to 5500 hz, and your tweeter from there on up. Again, number I just picked for exaple's sake.

With the 2 way, your two speakers have to be able to play a wider range of frequencies, opposed to a 3 way set where the frequencies are split up between 3 speakers, so each speaker doesnt have to play such a wide range of frequencies.
That doesnt really mean a 3 way set is any better than a 2 way set though. A 3 way set can have a musical advantage due to the drivers having a smaller range to play so there isnt as much breakup on the high and low ends, and where the crossover points are, but price, mounting options, etc of a 3way set make it less appealing; to me anyway. Whether one is better than the other is pretty much dependant on whos listening to them...