You owe it to yourself. I have been lucky enough to visit Portland twice from the UK and Powells is easily one of the top 3 memories from each trip. You will not regret it. Unless you find something it the rare book room you just have to have. Then your wallet may regret it.
100% this. People loose the wood for the trees with these kinds of things. If something doesn't work in one browser but does in another then 99% of people are not technical enough to understand or care why not. They just know it doesn't work. That makes it a problem for Firefox. Whether it's by their own making or not.
Times two.