Good question! I will be following this thread along which you as I'm curious what others have to say. I know the room will look bigger (longer) if the boards run vertically as you enter the door. But I guess it also depends on the subfloor and how the boards have to be oriented based on that - but not sure if that matters with engineered wood?

I am a DIYer not pro, but I think the rule of thumb is to run longways through the room (if the subfloor allows, i.e. perpendicular to the joists). In my old house (built 1959) we pulled up carpet to expose original hardwoods which were run the 'wrong' way, shortwise across the room. However, that was correct for the joist position. When we added flooring to the adjacent areas, in two halls and a kitchen, we went with longwise to each area, which means the wood ended up turned 90 degrees from adjacent areas in multiple places. So our floor was not 'correct' throughout but our installer told us it's really a matter of personal preference and he sees people do it both ways. It's also a dark color, so not quite as obvious I'm sure.

In our new house, we decided to make all the wood run the same direction in the entire upstairs, which meant that two rooms are 'wrong' running shortwise but the other three rooms and the hall are 'right' with running longwise. Our rooms are all good size so it is not visually shrinking the rooms too badly when it runs shortwise. Here is an article about choosing direction at an entryway. I would think about whether you want the wood to turn or run the same way throughout the open floor plan, and if you do run the same way, which areas are the 'wrong' way and will it be really negative in those areas? Like are those really high visibility areas? Or in the really small areas, like maybe a smaller kitchen, does it run incorrectly so will make it seem really small, but your breakfast room is OK and that is more important to you?

Here is a link that might be useful: link about flooring direction

From a pro prespective. I will not lay any wood floor that runs parallel with the joists. Unless i get strict instructions from the H.O to do so. But even then i explain my concerns.

If over concrete grade then i do whatever the H.O wants.

Have you thought about running the boards at a 45 degree? Get kinda brst of both worlds. Imo