We upgraded to the plywood it was only $130 more in our case. Something to remember though is when you upgrade they do not finish the ends you have to buy skins to finish them off. So in reality it wasn't only the $130.

My DH insisted on plywood, in the beginning I wanted mdf to spare the expense and put the money into other things. After much debate he was right. Ask yourself this, how long do you plan on staying in your house. Our reasoning was that we will be here for at least 25 years and would like the cabinets to last that long. Appliances and counters are much easier and cheaper to replace than cabinets. I would say something as substantial as cabinets would not be the place to save money. I ended up choosing a less expensive door style (ouch, the difference in prices are unbelievable) and eliminating a custom desk to keep the price more reasonable. Good luck, I know all this decision making can be overwhelming!

Funny. We chose our mid-line cabinet brand because they use plywood--not MDF. The more expensive line the designer carries is MDF boxes. The company using plywood is located in the mid West and they guarantee the cabinets to stand up to floods!

Well, there's more to it than just plywood vs. MDF. There's which plywood and which MDF. MDF is very straight and flat and a lot of cabinet makers like it for that reason. That's probably why Teched found the expensive line with MDF. It's also very hard to work with, very heavy, and most of it outgasses a lot of formaldehyde. Plywood has less adhesive in it so presumably less formaldehyde, can be worked like any wood, is less flat, more flexible, lighter, has grain, etc. Both come in different thicknesses. To get the same rigidity you generally need thicker plywood--is that good or bad? Depends on the usage. Plywood also comes in several grades, though I don't know if MDF does.

Then there's lumber core, which is only three layers (skins with solid wood in the middle), and looks good end on (good for doors).

I used to think plywood was "better" but then I realized that it was because I'm allergic to MDF :) There are plywoods and MDFs with very low formaldehyde, but the EPA is catching up on this issue.

Ply is probably better in some regards, much as solid wood would be better yet.

But I'm firmly of the belief that MDF is 'good enough'-- rigid enough, durable enough, moisture resistant enough-- for the vast majority of us. Better hinges and glides are a smarter upgrade, IMO.

..."much as solid wood would be better yet"

Wrong. Solid wood expands and contracts with humidity changes, and requires very different, much more complex and typically prohibitively expensive construction methods to make it work for cabinet boxes.

Good plywood can be very nice, but the cheap stuff can be awful. As plllog points out, there's no simple answer to this question.

Yup, like p111og and jon1270 say, basically, poor MDF is worse than good plywood, likewise, poor plywood is worse than good MDF. Between good MDF and good plywood? well, not sure that there is a better or worse. The MDF/PB boards for cabinetry can be manufactured with very low-VOC glues - mandatory in many European countries while the US-EPA is slow (as usual) to wake up to this fact, and as usual is being slowly dragged to it after California takes leadership on this.

But mostly as I understand it, there isn't much of a performance difference between PW and MDF/PB for cabinetry and you're paying the difference for your own preference/prejudice and that cabinet makers have decided to capitalize on :-).

GOOD cabinetry-grade PB/MDF is shrouded in melamine sheeting which is impermeable to water, easily cleaned etc, and bonded very well to the substrate. This stuff isn't going to decompose in a hurry and there have been plenty of folks here who've remarked that they're remodeling a kitchen with 20-30 year old (Woodmode?) PB/MDF cabinets that are in perfect shape but being removed for updating purposes.

Oh, and some of the priciest, highest-end and most up-market brands are the German & Italian lines of Bulthaup, Siematic, Snaidero, Poggenpohl, and the like. They're all MDF; good luck finding plywood in those lines.

I am one KD that does NOT capitalize on plywood upgrades. I usually recommend that they go with the mdf with the vinyl interiors. Put that extra $500-$1000 in your countertops, appliances or tile....or on the exposed wood ends of your cabinets. Make them 'matching doorstyle end panels'. I recommend this purely because it is what I would do in my own home. I've had both mdf and plywood (with veneer interiors) and I'll never pay extra for the upgrade again.

The exteriors of kitchens wear out before the interiors (usually, right???) Get a cabinet with a good finish...usually semi-custom or better.

I wanted and requested all plywood box construction from buycabinets.com and ended up getting mdf. As I have learned recently and observed, there are different qualities of MDF. The MDF that is in my cabinets is coarsely pressed mdf (flakes easily like sawdust), whereas the best quality mdf is pressed very tightly and is almost like a board. The mdf that I received (and didn't want) in the cabinets reminds me of the $79 desks you can buy at office supply places that you put together one time and if you need to move it, you better throw it away because it will fall apart.
I do have solid drawers and doors, but I really would like a plywood box or the highest quality mdf.
Please find a place where you can SEE the quality of your cabinets before you buy. I didn't and it was a huge mistake.

"The MDF that is in my cabinets is coarsely pressed mdf (flakes easily like sawdust), whereas the best quality mdf is pressed very tightly and is almost like a board"

Actually, the coarser stuff isn't MDF; it's particleboard. All MDF is tight and fine-textured.

But solid wood would never, ever delaminate: that's why I said it would be better 'in some regards'.

There is no 'perfect' building material, each has its strong and weak points. I personally feel that ply's superior resistance to moisture is somewhat oversold re: cabinetry. A good quality MDF cab will last a very, very long time barring a full scale disaster, like several feet of flood water, at which time the ply cab will also be a write off.

The real advantage of ply to me is if you want stain grade wood interiors. But if you like the easy clean, bright and reflective look of a melamine interior, a good quality MDF cab will perform well.