I tried the Casper pure foam pillow...slept well but a tad firm for my specifications.
Then ordered the Casper 'regular' pillow and enjoyed it, but a bit too cushy.
Finally, bought the Hybrid and found it to be just right.  For me, a perfect combination of soft outter and firm center that has me dropping into deep sleep most of the time right away.  And, importantly to me, combined with the Casper cooling pillow case, this Hybrid sleeps cool, even on warm nights.

Worth the expense for the sleep I'm experiencing.