For our team, we've found a nice balance between the two.
Firstly, we try to have a traditional spider layout w/ banked motor controllers for the drive train eg
The key thing is that the path from battery to all the drive motors is as short as possible. This means we usually end up with a layout similar to the above, except with only four-to-six motor controllers in the banks.
The rest of the electronics is more loose. We quasi centralise all the "intelligence", namely the roboRIO, radio, camera-processor etc. mainly for convenience. However when using the SRXs, we prefer to place them as close as possible to the mechanisms, keeping sensor cables short.
This allows us build mechanisms complete with most of their electronics, so that we only have to connect/wire power and CAN to the rest of the robot. It also has the secondary advantage of not needing to deal with all the SRX CAN wires when they are right next to each other.