Like Leg Levelers, the Suspension System, which consists of steel rail you mount on the wall and suspension blocks that install in the upper corners of the wall cabinets, you can get your wall cabinets perfectly level and plumb. Again, 3mm or 1/8" reveals between doors and drawer fronts are very unforgiving.
One frequently overlooked feature of the Suspension System is that it allows for a single man installation crew (the modular nature of Full Access cabinetry allows for a single man delivery if you ever get tired of paying people to look at the back of a windshield on the way to and from the job-site each day).
The Suspension Blocks have two screws in the face of the block, the upper screw allows you to raise and lower the cabinet, the lower screw allows you to plumb the cabinet. Once you have the cabinets level and plumb, you simply slide covers over the block, making it aesthetically appealing (if the house settles over time, the Suspension Blocks allow the cabinets to be tweaked to accommodate for the settling).