It definitely is a luxury system (and probably not within the OP's budget), but it has some refinements that really make a difference:
1. When you have multiple units, the entire network acts as a single, seamless system. You can play different music on each unit, or a tie group of units into a "zone" that plays the same music (with centrally controlled volume level), with the music perfectly in sync between units (this is technically quite difficult to do). I'm not aware of any other system that does this...
2. The Sonos units form a wireless mesh network, so you don't have to have perfect wireless coverage everywhere you put a unit, as long as each unit is within range of another. This is very helpful in the large houses of the people who can afford these things. One unit does need to be hardwired.
3. The remote is very well done. Having an iPhone remote is great if everyone in the house carries one, but that's rarely the case.
4. It plays very well with NASs. It can read your iTunes playlists, and because there's no local storage it's one less music repository to sync and maintain.
5. Sound quality is very good. They handle lossless formats, and the internal amps are decent.
Anyway, it's a fantastic system if you've got the money to burn.