well i just got mine in as well and here is my quick review. i didnt have time to mess with the placement of the satellite speakers. only the sub and let me tell you placing the sub in the right spot makes a world of a difference. i used to have it somewhat under my desk and i decided to move it in the open next to the corner of my 15x12 room and 1/4 of a song later 3 of my friends came to my room to find out what was going on. (this was the part i stuck out my chest and said yeah wassup )
ive owned the 2003 5.1 before the amp failed to work so let me tell you what the differences are. first the pod doesnt skip as much as the other one did. there have been a few times with the original 5.1 it would jump from like 30 to 22. gets real annyoing when your trying to fine tune the volume. second the satellites sound pretty close to the old 5.1. the difference is noticeable when there is nothing playing and you have the speakers on. the hiss seems to be almost nonexistent thus it is perceived as being clearer. classical music/piono music will allow you to notice the lack of hissing when there is a pause in between notes. it is probably do to the rewiring they did to the satellites.
last but not the least is the sub. this is the major difference between the ultras and the old 5.1. the ultra sub sounds as if its more rounded than the old 5.1. it could be that it hits slightly lower than its predecessor which gives it that "completeness". sure it wont shoot out that brown note like many of the $1000+ subs where you feel your heart shaking but it gets pretty damn close. these are the only differences i was able to tell between the old and new 5.1. either way, your not going to go wrong. i wouldnt have mind if they just replaced my old 5.1's but they gave me the ultras. im not going to complain. hope this review is helps.
(sorry about the long post but i felt that many other people are looking for a comparison review which i have yet to find on the internet)