I had a read through this thread, wanted to add some comments/observations. I totally get the criticisms of MDF and the preference to use furniture grade plywood etc over it, however... MDF can be a really good choice as well in making cabinets. I regularly use all kinds of timbers MDF, different grades of plywood, solid timber - hardwood, softwood, whatever.
I agree absolutely with Alejo I's comments. MDF in combination with the right surface treatment yields really nice results. It is grain free and can be shaped really well. Whilst it does not hold screws well, can de-laminate when subjected to pressure along its edge, absorbs moisture and swells and has a binding agent which is a toxic lung irritant it still has desirable features over other materials in certain instances. It works really well with fillers like Bondo and high-build automotive primers. I've found (much to my annoyance) that plywood can warp underneath a finish and distort it. This never happens with MDF given the same treatment. Panels that are glued with MDF glue are really strongly joined together especially rebated joinery.
On kitchen cabinet builds. Here in Australia MDF is generally not used to make kitchen benches or cabinets, instead high density (chip) particle board is used. The same stuff they used in making original arcade cabinets. Cheap loudspeaker cabinets are made of the same stuff. High quality speaker cabinet makers choose thick MDF to build with as it has excellent acoustic properties and is better for rounded off edges.
Should you use it to build your cab from? Maybe. If you intend to laminate your cab or just use a roller paint treatment I would say no, go with a reasonably good plywood instead. If you want to produce shaped forms, curved edges or cut-outs and intend to seal and spray paint the surface, MDF is an excellent choice. You need to use proper PPE with MDF, that's kind of a no brainer.
It does NOT look great with a sloppy paint job, it looks terrible, kinda fuzzy and rough!