We went with a Bona sealer and finish, totally clear. I'm really glad we kept it clear. They didn't darken at all (although they look a tad darker than when they were bare sanded, maybe because of all that sanding dust :) The floors are not perfect, and have a few stains and lots of dark nail holes, but they are 104 years old! They have character. We have had grain rise problems with the Siberian white oak, but I guess it's typical with oaks. We are still working on the plaster walls, ceilings and windows. After all is done, except the quarter round, I'm going to buff, dust well, and apply two more coats (with another buff in between).

All stain colors go in and out of fashion. I’ve had three wood floors in three homes over the past couple of decades. The medium/natural tones seem to be more timeless. Dark, almost bare, white-ish and super dark espresso all are fads. Grayish brown is too. Keep it natural with a light stain. Your floor person absolutely needs to test different looks in your house before you say “go”. All wood is different after it’s been sanded. Yes, this is a huge, expensive one time decision. Good luck.

If you like your current colour then go ahead and put down a new version of it. If you want something different then I would go lighter. I love the look of red oak in the 'buff'. It is a pretty wheat/sand coloured wood. So long as you work with a high-end water based polyurethane that does NOT yellow, you will have a very pretty 'pale wood' floor without much effort. Your existing finish appears to be oil based (or oil modified) which makes the floor yellow. The strong gold tones in your wood right now = the finish. Did your refinisher apply a coat of FINISH over your colour samples? If they did NOT....then you are picking BLIND. And I mean screaming and crying and tearing your hair because your beautiful gray floors turned to a muddy orange mess. Not good. Do you see the pale colour of the raw wood? You can keep that colour (very close to it) with 3 coats of water based polyurethane like Bona Traffic HD. Keep the gloss level a snick on the low side (satin is a nice low-gloss option) and you keep that pretty 'swedish blonde' look.

Haven't specified yet exactly which one with the contractor, but they said they can use Bona which is what I was leaning towards. I was looking at Bona Nordicseal and and mega one like you recommended to try and neutralize the red/yellow tint as much as possible without a stain. For some reason they only specified two coats of finish for the natural job. The other quotes I received that included a stain had three coats of finish on the quote. The natural job with water based finish was significantly cheaper compared to the one with a stain. About 1.5-2k difference.