Director Redundacy options? VRRP, heartbeat, ldirectord?

[Sean Knox <sean.knox@xxxxxxxxxxxxx>]

Hello all,

   I have been evaluating the various failover options as of late- I 
wanted to get other's opinions and the pros/cons of using one solution 
over another...namely, VRRP, heartbeat, and ldirectord. Currently we use 
heartbeat in production, and it works well. I'm curious to how well each 
of these will scale, and of course, the stability of each option. Any 
and all insight is appreciated- thanks!
Sean