The most important thing is the craftsmanship of the cabinetmakers. Ask for testimonials and look at previous installs for perfect joins, nice straight lines, smooth edges, no gaps or overlapping. You will probably find that most cabinet makers use MDF so the only difference is the thickness. Obviously the thicker the better. Make sure you get solid backs (not stapled thin Masonite). The hinges and drawer runners etc can vary in quality a lot so you will want a reputable brand, and preferably soft close. And remember that the finished result depends on multiple trades working together well – eg plumber, electrician, possibly also stonemason, tiler and glazier – that need to be coordinated and not destroy each other’s work!