I find equipment between the loudspeakers distracting, almost as much as a blank TV screen. When my gear was between the speakers and included a big McIntosh amp, I found myself putting the record album cover in front of the amp so I wouldn't have to look at the meters, especially when the room was dimly lit.
Aesthetically, I find it much less overwhelming with the speakers placed separately. There's also a little more flexibility with fine-tuning the speaker placement.
All in all, I listening to my system more when I don't have to look at the pile of gear.