solid wood is 3/4" thick. You can sand down to where the nails are which is where the 'tongue' is. Engineered wood is 3 5 or 7 plys with a veneer of hardwood on top. Its generally more stable than a solid. There is no intrinsic advantage of a solid over engineered, though there is a perceived difference as one is 'thicker'. That has really nothing to do with anything. Factory finishes are generally far more durable than anything you can do on site. Unfinished allows you to stain any color and sanding will make the floor real flat and smooth. Prefinished you can't pick stain color other than the std colors, and generally will have overwood if the floor isn't perfectly level. As anything in this industry there are tradeoffs to all flooring materials.

Find out the wear layer for the engineered hardwood. That will help determine which is the better deal and product for the $$. Annied75 is right in that pine is a soft wood. It is not as hard as oak flooring. However, with that being said, all hardwood is susceptible to wear and tear and will show it over the years. The reason I ask for the wear layer is because it will help us determine how many sandings this engineered floors can withstand. The engineered floors we provide for our customers have a wear layer the same size as solid hardwood and therefore can withstand the same amount of sandings before reaching the tongue of the hardwood. If your engineered floor has a thin wear layer, the solid pine flooring just may be the better product for the money you are going to be spending since the pine floor will be able to withstand several sanding and refinishings. However, I read that you are going to be installing this over a slab floor in Florida. Since that is the case, engineered flooring is the way to go unless the pine flooring is going to be milled in an engineered version. Ask Hardwoods for Less if they can send you some samples before making the large purchase.

If you want the STRONG GREY colours shown in your photos, you will need to work with factory finished. If you like the liming or cerusing effect (the white in the grain) then you will need to work with the factory finish. I've heard of a small handful of HIGH-END professionals who can achieve these looks on a site-finished floor. If you think that the population of the US+Canada is around 375,000,000 that is a SMALL amount of humans....like 100-150 professionals who can handle a job like that. Imagine the price tag! We will see this level of workmanship on $25Mill homes. The price of the professional is not at issue in a home that has multiple millions of dollars in financial backing. I understand your Project Manager's concerns. Repairing damage to a factory finished floor isn't fun...but it isn't difficult either. The worst case scenario = cut out the plank and drop another one in. A bit of glue...a bit of waiting and everyone's happy. I'm not sure why the push back is so hard (the PM has probably had something go wrong in the past and had it bite him/her in the arse pretty hard). So long as you assure him/her that you will pay for all the damage control (ram board, etc) you should be fine.

Engineered hardwood flooring is indistinguishable from solid wood flooring from a "look and feel" perspective. For planks as wide as 8-9" I'd be surprised if you could find solid oak planks. The only difference to consider would be the ability to refinish solid floors several times where most engineered products would allow for a single refinishing. Engineered flooring is generally a plywood base topped with the finished wood and arrives pre-stained and finished, ready to lay in your home. There are usually options for how it can be laid, nail down, glue down, floating etc. Solid hardwood would offer the same options. Some engineered flooring is not recommended in below grade applications. Solid hardwood can be found both unfinished and pre finished. Unfinished would be laid in the home and then sanded and stained to your desired colour and a finish coat on top. In my opinion, engineered hardwood is the superior product for most applications. If you are unsure, go to a good flooring store (not a big box) and see the various options available and talk to a flooring professional at the store for the best recommendations for your situation, including the subfloor it will be laid on, humidity levels in the home, desired look and feel (do you want a very smooth floor or maybe some distressing in the finish etc). Don't hesitate to choose Engineered. It is not a "cheap out" option at all and may be end up being a better option than a solid alternative.