My experience with Waterlox is that it does not yellow over time, I actually think the initial amber hue fades slightly to a more transparant color over several weeks as the varnish polymerizes. When I put Waterlox on new Baltic Birch ply or other light color wood veneer, the initial look is considerably yellower than the fully cured product, which is pretty much clear.

In use, it seems not to yellow. Whether this is because of its chemistry, or because it is a thin/penetrating type finish (poly is thicker, less penetrating) is left to speculation.
Casey

It also depends on what type of poly.

Solvent (oil) based poly is more yellow and often yellows more depending on UV exposure.

Water based poly is usually more clear and does no yellow as badly (if at all).

Hi woodworkers

I am mulling over an island (116" X 54") made of walnut planks laminated together. My other option is granite. I will have a copper sink in the middle and two dishwashers. I have two boys, age 12 and 13. I love the look of face grain walnut (especially stained-even though it is a gorgeous color naturally). My GC seems very high on this idea but I am worried about maintenance, etc. A guy at Expo where they had a similar countertop said they have to refinish their store model a lot. And of course, that doesn't get eaten on, have a sink in it, have kids doing homework. I realize edge grain is the other more durable way to go (I like the look less, but would be willing to do it). Either way, since this will be my main working area (I have some countertops on the perimeter, such as an area for putting pots after the stove, which will be granite) but this is obviously the huge center of our kitchen. What do you think?