Everybody has been going back and forth between two approaches to "best class" -
Best by rankings as of signing day vs. best in retrospect (college career, though you could do it for NBA as well).
I think that leaves out another third approach which is more useful than either. It avoids the "only available in hindsight" facet of the retrospective and also avoids the "but Dakari and the Twins were ranked so high mostly because they matured earlier", which pops up when just listing recruiting numbers.
The third approach is taking rankings at the time of signing *while considering the quality of the recruiting class as a whole*. It's still not perfect, but it's certainly better.
So, for example, in '13, there were 3 guys (4 if you include Aaron Gordon) who were considered eliiite - Wiggins, Parker, and Randle. By their senior year, there was a pretty steep cut off from those guys. We got one, and he performed like a beast. The rest of our guys were more typical skilled freshmen who fluctuated over the year.
In a crazy good class like 2015 (or 2007), there might be 8 or 10 guys who would be in the conversation for #1 in a really crappy year (eg. 2012, where the top 5 besides Nerlens were Shabazz Muhammad, Kyle Anderson, Isaiah Austin, and Steven Adams
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).
So while '13 was very good at the very top, it wasn't anything like this year. So getting 4 top 10 kids in both classes is really no comparison. And we don't really need hindsight to see that - we knew who the standouts were for that class back when they signed.