Again, laser vs. hand held.
My 40's POV is largely informed by the constant, year-in, year-out drop in 40 times reported vs. what is actually posted at the combine. We think 4.6 is slow. A true 4.6 certainly isn't blazing for the NFL, but it isn't glacial either.
And one anecdote I got straight from a former GA at Florida State. He told me he'd seen exactly 2 true 4.3's in his time as a coach and player. One of those? Deion Saunders.