It's good, but we are a long way from comparing it to historically great classes. I'd be quite surprised if it ends up better than 2015. 2016 wasn't viewed as amazing a year out, but the top end ended up being quite elite.
I expect 2018 to look maybe comparable to 2008 and 2009. The big issue with 2018 is that the best prospects are (Dahlin and Svechnikov), one is a high-risk position to project (defenders) if you look at the mixed history of highly hyped defenders (EJ, Doughty, Hedman, and Bouwmeester) and the best forward prospect is a winger. People had high hopes for Veleno, but at the moment, I wouldn't project him as a sure-thing franchise center. If you look at the good drafts in recent years, almost all have been anchored by having a sure-thing #1 center at the top, possibly even two. Look at 2016 (Matthews), 2015 (McDavid and Eichel), 2013 (People projected this for Mackinnon, but there have been arguably 4 #1 or at least 1B/2A centers in the top 10), 2009 (Tavares), and 2008 (Stamkos).
Kids like McBain or Veleno could end up being that level of talent, but they simply aren't right now.
This draft is very deep defenders wise, which is good, as that is a need league wide, but projecting defenders tends to be very difficult and high-risk. 2012 didn't have a Dahlin level talent but look at the scattered results of the top 10 of that class (Murray, G. Reinhart, Rielly, Lindholm, Pouliot, Dumba, Trouba, and Koekkoek).