Go for sonos for these reasons:
1. 2*P3 work well and sound very good, better stereo imaging than any doc system
2. Uses its own network, does not suffer from dropouts if son is on PS3.
3. P5 is also portable (zep isn't portable)
4. Controller software is free and works well on smartphones.
5. it is expandable (which you will do when you get into it) and soooooo simple to set and use.
6. it has far more music services that increase what you listen to, experience and eventually buy.
7. Customer service/dealers are excellent.
I went for Sonos after two years of procrastinating and research/trying out, and withut sounding cheesy it is the best decision I ever made.