SI's Chris Mannix in his NBA Draft Big Board has Len listed at #12 overall, which to me seems about right at this point in time (mid-first rounder). With the recent Dez decision (stupid NCAA), we'll need Len to play at that level throughout the upcoming season.
Len's numbers don't jump off the page, but team execs are high on his defense (2.1 blocks in 21.2 minutes) and are eager to see him play a more expanded role. "I really have no idea what he can do offensively," an executive said. "But he plays lottery-level defense and I think his offensive game could really develop this season."
Edit: Added a poll for fun.