Buying leftover bikes is a double edged sword in my opinion. The question you should ask yourself is how long you intend to keep the bike. Resale value tends to decrease rapidly the first few years and then stabilizes.
So if you were to buy this '17 and sell it in 2 years, you would get resale on a 3 year old bike, which would be quite a bit less than for a 2 year old bike (at least around here). It seems llike 2 years is kind of the cut off for a "recent" bike. But if you were to keep this bike for 5 years or more, the difference in resale value would likely be marginal, plus by then you have to factor in the countless hours of fun you had on the bike over those years.
So long story short (in my opinion):
Intent to keep the bike for
2 years or less: Buy '18
3+ years: Buy '17 if the price is right
*Anyone but Reed or Webb Crew*