Whoa. Those questions will require pretty much an entire education in wood and furniture construction. Don't be too hard on those salesmen. Their employers are just buying stuff from a factory and don't educate the employees about the products. There's a lot to learn in the woodworking field.

1. The short answer is that neither solid wood nor veneered furniture are better. Badly made furniture is bad and well crafted furniture is good.

I wish I could locate the original source, but I've been informed that studies conducted by the Smithsonian revealed that veneered furniture tended to survive longer than solid wood pieces. I cannot find the source but I suspect this is because a lot of solid wood furniture is built for utilitarian purposes and is more likely to be tossed than many veneered pieces which can be highly decorative and are treasured by collectors. A lot of the period furniture found in museums use veneer and those who aren't woodworkers just assume it's all solid.

Veneer got a bad reputation due to companies like Sauder that mass-produced a large quantity of cheap furnishings by covering flaky particle board with thin veneers. This is not the fault of veneer that it was used poorly. Other companies stuck veneer across pieces of solid wood then humidity-related expansion and contraction caused it to fall off.

Solid wood is assumed to be superior by many because dents and scratches can be sanded out and refinished. A gouge in solid wood doesn't look as bad as a gouge in veneer that reveals mdf underneath. However, solid wood does have a major limitation in that it shrinks, grows, cups, twists and warps as the humidity of the surrounding environment changes. This movement cannot be prevented, it can only be directed. Sometimes uneducated designers attempt to force the solid wood to stay in place to get a particular aesthetic and this results in furniture that self-destructs. Those designers should have used veneer instead.

Veneer is thin enough that the movement can be eliminated by gluing veneers to both sides of a stable substance like plywood, mdf or particle board to create a panel that remains pretty much the same shape and size at all times. The thin veneer cuts also make it possible to take one highly figured board and arrange the slices of it into matching patterns. If you ever see furniture with the grain arranged in patterns, it is likely veneer.

So the answer is that solid wood is best used in places likely to be abused while veneer is best used for decorative reasons, or for surfaces that need to remain stable to prevent the furniture from breaking itself apart. When I do veneer work, I make sure that I put pieces of solid wood in the corners and other areas likely to get damaged. This utilizes both materials to their best advantage.

Furniture that is destined for heavy abuse is best made from solid wood. No one would want fancy decorative patterns on utilitarian pieces anyway.

2. Just about any kind of material can be used underneath veneer. MDF, particle board, plywood and solid wood are all common. Each one has advantages and disadvantages. Your concern about mdf is somewhat on target, many of them do contain a lot of chemicals but that is true for most engineered woods including plywood. These days it is possible to get formaldehyde-free versions. Also, professional lumber suppliers sell mdf and particle board that are much tougher and more damage-resistant than the stuff used in cheap furnishings.

MDF:
This has the smoothest surface of the commonly used substrates for veneer. It is a stable material that won't change much in length or width as humidity changes. It has the advantage of being easier to work with than particle board.

Downsides are that it is more likely to sag than most other substrates, is heavy and with the exception of water-proof versions, water will damage it quickly. In practice, a properly made veneer panel will prevent water from reaching the MDF core unless it's subjected to standing water for some time.

Particle Board:
This is much lighter than MDF, is almost as smooth on the surface and is less prone to sagging. It's more of a pain to work with however and the edges are easily damaged. If the edges are protected by solid wood, that becomes a non-issue. Like MDF, it is very stable.

Plywood:
Strong, durable, stable and usually much lighter than MDF or particle board. The downside is that the surface is not perfectly flat or uniform and this sometimes shows through to the surface of any veneer applied to it. Those large, dead-flat conference tables with mirror finishes likely have mdf or particle board under the veneer and not plywood.

Solid wood:
This is a viable option but veneered furniture made this way loses out on the stability advantage of engineered products. Veneered solid wood will more or less act just like solid wood. No one will get a modern conference table with this technique. If you see this, it's likely done to save money on materials by using cheap wood then applying a skin of expensive wood over that. Sometimes the veneer is a rare exotic species which is only sold as veneer.

That poplar and cherry veneer bed frame? It could very well be poplar with a skin of cherry. I'd have to see it in person to know.

3. I don't know anything about that particular brand of furniture so I can't help with this question. If it doesn't specifically say that cherry wood is used, then it's probably a cheap, lightweight material that's been stained to a "cherry finish".

This post was edited by JAAune on Sat, May 31, 14 at 21:36

OP, hopefully you have made your decision by now.
For future readers I would like to point out that at this moment I am surrounded by late 60's hardwood and veneer furniture which I had to refinish due to abuse and 2nd hand smoke. Yup, it had a terrible film on it and a number of rubs andnwear points.
It lasted the purchasers a good 25 hears in good condition then needed refinished. Since it has done me a decade or so in great condition.
I am annoyed by the old drawer guides and find full extension side roller bearings (think high end snap on tool box) to be superior to metal or wood tracks.
If you are thinking in a couple decades you'll have to refinish it, plastic or the new poly resin mouldings annoy me. Lowes will even sell you cheap wood carvings! FWIW, the new poly resin reminds me of hockey sticks which take tons of abuse at least.

Does anyone know what radiata solids is supposed to be? A good wood or bad wood?