As I said your options depend on your application.
Now that you've been more specific you have to consider that 1/2" MDF will be weaker than the conventional 3/4". Add to that, countersinking will weakens the MDF further.
Why have you settled on 1/2" MDF? 1/2" plywood is lighter.
And why use 2" x 4"s for the frame?
The MDF from places like Home Depot and Lowes is the cheapest stuff on the market and is very easy to fracture with a screw that is too big for its pilot hole. And confirmat screws were made for something like this, but you need a special bit and a drill guide.
Nevertheless, since you want to use drywall screws, you will need a way to hold the cabinet together when you drill the pilot holes. Hole accuracy cannot be understated. And be careful with the drywall screws. They are brittle and will snap when they are over torqued.
I'd use dowels myself. Dowels are actually far stronger. Even stronger than biscuits. If you had a good dowelling jig you wouldn't have to worry about countersinking. Of course this would take longer and really isn't for the average newbie woodworker.
Staten Island, New York.
I don't want to be a jerk, but all the advice here (except that plywood is lighter) is wrong. A 2x4 frame is a great idea. Makes for a very sturdy cab. 1/2 MDF is plenty strong and as far as hole placement you just have to be close. Dowels make for cleaner work, but a dry wall screw is plenty strong. I built a cab. It is still around after 5 years or so. Check out the link ...
Note the 2x4 frame and how it is built. It looks like you collect cabs, have you made any?
I don't have to make any game cabinets. But I've repaired enough of them.
And you would
be a jerk if you called someone's advice wrong and not address specifically what advice you think is wrong and why.
I never said using 2" x 4" for framing was a bad idea. I simply asked him why he settled on it.
I did say that 1/2" MDF is weaker than 3/4" MDF, and
having to countersink will weaken it.
Of course plywood is lighter than MDF. He conveyed a concern with the weight of the cabinet. Plywood also holds screws, nails, dowels, etc., better. Plywood would also repair better. And MDF releases urea formaldehyde when sanded and cut. The health implications of that are well known.
(I personally wouldn't use drywall screws in MDF, but perhaps my joinery standards are just higher).
And downplaying hole placement demonstrates that you need to learn more.
Having a cabinet for 5 years means nothing.
But again, what advice did I give was wrong?
Staten Island, New York.