Are European white truffles significantly superior in flavour to those from North America? There is a rumour that white truffles harvested in Europe by pigs or dogs are much better in terms of flavour than those from North America, hence the reason for the higher price of European white truffles, the main reason given for the aroma difference is that it has something to do with the way the Americans harvest their truffles.

Are European white truffles much more aromatic and flavourful than the North American ones? I would like to try truffles but I do not want to spend too much money on the European ones if the American ones are just as good or nearly as good.
I think the truffles that are exported are of better quality on average than what you'll find on the european market. I've never tried the american ones consciously (they're not imported to Europe as far as I know).

You could also take into account that the fresher the truffles are the better the quality, so in theory it would be better to eat american truffles in the USA and european truffles in Europe.

Given the mind boggling price differences and the supposed high quality of the stuff found in the forests in Oregon, you're likely going to be well off picking the local stuff.