The look and function of even high quality cabinets can be ruined if they are not installed properly.Cabinets that are out of square, not level, or with improperly aligned doors or drawers can cause binding, rubbing and breakage.Frameless and inset styles have more precise margins and require more time and a higher level of skill to install properly. A good installation is tightly scribed to the walls and floor with no gaps and fillers. Doors should have even reveals and swing freely. Drawers should function smoothly. There should be no dings or mars in the finish. Installers should clean up the job site and seal off other areas of the house from dust.
Are the cabinets being installed by an employee or a subcontractor? Subcontractors work on fixed bids and may be more inclined to cut corners or be less experienced on the type of cabinetry they are asked to install. This is not always the case, but something to be aware of.
Ask about service policies in case something needs work a few years down the road. Check references to make sure the company stands behind its products.