In my machine, the Z axis linear guides are located at the center of the bed. I didn't want to cantilever the adjusters out to the far edges, and as a result, adjusting roll moves one edge up and the opposite edge down as the bed pivots on the reference and pitch adjustment screws. Adjustment would be easier if the reference and pitch adjusters were located opposite the roll adjuster, but the adjustment only has to be done once. Putting the reference and pitch adjusters right next to the Z axis bearing blocks makes for very stable positioning and it doesn't require readjustment unless I take the machine apart. I use springs to hold the bed plate down on the leveling screws. If a really massive print were printed off center, it's possible for the spring at the roll adjuster to stretch and let the bed tilt, but in the real world that's not going to happen.
I guess either type of mount would work fine. As far as I can see, both types have a single stable position for the bed at any temperature. I wouldn't expect to be able to resume a print after a power failure if the bed is heated simply because prints are going to come off the bed if it cools while the power is down.
