rj -
i've listened to the 2.1s but i'm sure there are similarities between the two.
For one, they are a very neutral speaker and are very musical. Build quality and looks are exceptional - those little "bookshelf" speakers weighed 31lbs a piece. I closed my eyes while listening to some acoustic guitar stuff and the music just floated in front of me. It was really wonderful.
The only downfall, if you will, of the 2.1's was their lack of a midrange - not a complete lack but there was definitely a "hole." However, the 5.2's have two 6.5" drivers as well as a midrange driver so I'm sure that gap is filled. Also, b/c the 2.1's are bookshelf style speakers, they didn't extend too deep - but that's not the concern.
Hope that helps
Christian
