We looked into the more complex systems, but their cost just didn't make sense to us, we only use it when we have parties or when we are cleaning... As far as convenience, my system runs through my home theater, so All I have to do is hit the power/zone2 button on the processor and turn the ipod on... Then I only have speakers in the kitchen dining room and upstairs loft {then a few zones outside, we have 4 porches, so the vol controls are by each door}, so if you are going to want the speakers on in the room you are in, you have to walk by the vol control so its not a huge deal to click it up a little... then down when you leave that area...
Another problem with the more complex systems besides having lots of parts that are prone to breaking {in my experience, this may not be the norm, but when I had the more complex system it was a nightmare}, being 10 times the cost, harder to install and run, is they get outdated. With the basic system there is nothing to get out dated.. A customer of mine {I build houses} bought a high end nutone system, about 2 years later the main panel died and they didn't have a replacement, and couldn't fix it, I don't remember the entire situation, but I remember it costing around $1500 and they had to have painting and plaster done because the new unit was a different size...
The basic system works well for us, its super easy to start up and very reliable... Also if anything breaks your not calling the electrician or alarm guy, its either a wire, vol contrl or speaker... Not some ecm module tucked behind some panel somewhere..