A few years back I also did some experimentation with phantom on/off and with center fill adjustment. My processor allows me to use a center, but have some percentage (anywhere from all to none) sent to the L/R speakers as well.
In my room, I found that if I'm the only one watching a movie, I liked the phantom center the best. The center channel seemed to blur the image, and iimaging and soundstage suffered. But if you have people outside the sweetspot then the image tended to shift to a hard right/left which is annoying. However, I still use a center when people come over and watch movies. Even with a center, I preferred to use some center fill on the L/R speakers as it sounded more seamless than not having that adjustment.
I can assign multiople configurations on any input on my HT Processor so I can easily go from one to the other without having to change a menu option.
