I didn't see much of a difference in quality from tiers 3 to 5. The talent level isn't differentiated enough to be that specific. Motiejunas and Selby from tier 5 could end up being better than any of the tier 3 guys. So could Alec Burks and Biyombo.
Of the top 2, I like Irving a lot. He doesn't have the uber-athleticism of the top flight points right now and that's what keeping projections down and there is merit to that. But he's a big point guard with a lot of craftiness, shots, vision, a high basketball IQ and above average athleticism. The two things I like most about him is his vision--it's very good--and his proficiency at all three levels of shooting. For a young guy, he's got a ton of shots and polish and again, he's big. He's getting a lot of very good point but not all-star point projections but I wouldn't be surprised if he makes three or four all-star teams before he's done, maybe more.