Memory Foam or Latex Foam Mattress

We need to replace our old memory foam mattress.  It's beginning to sag after many years of service.  I'm a fan of memory foam, the way it changes shape to your body.  But it definitely begins to sag pretty quickly.  They're not great in terms of longevity.

I've been reading that latex foam mattresses are pretty good.  They're much more durable but have a different feel to memory foam.  They're bouncy.  Memory foam is not.  Are latex mattresses any good?  Has anyone tried them?  And, how do they compare to memory foam.