While people certainly write positive online reviews of restaurants, hotels, museums, etc., I agree that they are much less likely to take time to write about an unremarkable flight. I know I don't. So online reviews of flights definitely skew negative - for all airlines. Assuming you're flying coach, I don't think there's a great deal of difference these days. I find the non-US carriers slightly better, but not enough to make me choose them if there's much of a price difference. I've read that that the business and first class products can be quite different; I have no experience with these. However, even if you're not going in these higher classes, some carriers offer Economy Plus or Premium Economy (two different things), which can be about $75 to $300 more each way, and thus can be an affordable upgrade. If you are interested in this, then which carrier you choose definitely makes a difference.
One major difference between carriers is what's included in the base fare. Legacy carriers like United or KLM will include one free checked bag, a meal, and (usually but not always these days) seat selection. A budget carrier like WOW or Norwegian will charge extra for all of these. So, do be sure you're comparing apples to apples when looking at prices.
I agree that before you even look, we need to know why you are looking at a one-way flight. If it's because you're starting somewhere besides Amsterdam, definitely book this all on one ticket as "multi-city," rather than "one-way" or "round trip." The budget carriers don't charge extra for one ways, but the legacy carriers sure do.
Aer Lingus often has low prices from New York. I flew them last year to Glasgow and Liverpool, and they were fine. Coming back on them, you go through US immigration and customs in Dublin; this takes some time, but then your arrival in the US is like a domestic arrival, so you save time at that end. Turkish Air also often has low prices; they were wonderful to Istanbul, but going via Istanbul to Amsterdam would take a LOT longer. And Aeroflot often has low prices. I've been on their JFK to Moscow flight and (contrary to lots of old stories), it was fine, and at least as good as a US airline. However, I've never changed planes at Sheremetyevo (doesn't look like fun) and I've never flown them on any other route (I assume since they compete directly with Delta on this route, they use better planes, flight attendants, etc).