There are several misconceptions here. There can be site finished solid wood or site finished engineered wood. Having it finished on site is the variable. The two are not mutually exclusive. Foundation type often demands engineered wood, and that does not mean accepting a lesser quality material. As long as an adequate budget is in the picture, quality in either type is achievable. Site finished has everything to do with finding the right artisan. Prefinished has everything to do with the company that creates the product. It is a shift in emphasis for responsibility of a successful install. A NWFA accredited installer and installation for site finished is likely to be several notches in expense above the install of a medium quality prefinished product. Choosing to use a lesser skilled finisher simply because of budget, will likely have results that you are not happy with in the long run. Engineered wood, if it's a good quality, is indistinguishable from solid wood to the naked eye. IF it's installed as a Permanently affixed nail down or glue down. Floating floors are a whole other category of installation and often perform unsatisfactorily because of improper site prep and low quality sound pad. That is regardless of the material being floated, including laminate. Any floor that is not flat enough, and experiences bounce, is not flat enough for Any floor but carpet to be installed. Deflection though, often has more to do with the joists being inadequately specced to the lowest allowable by code rather than the subfloor thickness. When hard floors are desired, the home has to be engineered to accept them from the design phase. This is one area that being "code compliant" results in too many problems down the road because the code is inadequate for the construction level that most homes now wish to have. The use of a good quality vacuum is a recommended care routine in addition to dry dusting. If there are no other issues in the home, such as inadequate kitchen ventilation, a vacuum will remove dust from any micro bevels in a prefinished floor---or the inevitable micro gaps in a site finished floor.

I happen to be someone who installed both BR111 (Timborana) and Bellawood Bloodwood and Bolivian Rosewood. The ground floor is slab so I needed engineered wood. I am super happy with both. The Timborana is much softer than both Bellawood. The Bloodwood and Rosewood are about 3X harder than Red Oak so this is not a surprise. You can literally drop anything on either of the Bellawoods and I challenge you to see any dents. The BR111 Timborana is absolutely gorgeous and looks better than mahogany. We are super careful so in spite of both floors being 16 years, they look great and I still get compliments on the Timborana. It literally looks like fine furniture wood. I would not use it if you have children and pets or you are super rough on your floors. We almost never walk in with outside shoes and as a result it has held up well and only a few deeper dents and scratches. If you are not on slab and can use 3/4" planks in the heavy traffic areas, then by all means go for the Bellawood. I think it will outlast the house by another 50 years .... it is that good. The only advise I would say, if you have a Bellawood plank that is bent significantly, do not attempt to push it into shape with the nail gun, just set it aside and use another. I am not talking about slight misshapen, rather about ones that are 1/2" because sometimes they will resist so hard, you will spend 20 minutes on one plank. Luckily there is only a tiny percentage that are not straight. Overall both are great but pick the best according to your intended use

I currently have a prefinished wood floor in my kitchen, and am switching to site finished in my remodel, in order to match the wood in the rest of the house. After I decided to do that, my contractor pointed out that I would no longer have to worry about crumbs, dirt, etc getting stuck between the planks. I was really happy to know that, it was something that I hadn't thought of. The downside of site finished, as I discovered when I had the hardwood floors refinished in the rest of my house is the fumes. We had to move out of the house for several days when they were doing the work. Hopefully it won't be necessary this time because it's only the kitchen. As far as the sustainability of kitchen wood floors, I've had mine for over 15 yrs and it looks really great. I love it because it is less hard on the legs/back when standing cooking/baking for long periods. Also dropping something on it does not have to lead to the item breaking, another benefit.

Could be anything. Was it glued down? If that's the case tiny glue smudges that didn't get removed. Try Mr.Clean's Magic Eraser. But extra planks in the garage doesn't fit in that scenario. Why are they in the garage anyway? Poor place to store, unless you have plans to move them.