The caching seemed to work reasonably well, but the conflicts with PHP's APC and frequent encoding errors forced me to replace it with W3 Total Cache.
I tried proposed fixes that required updates to PHP.ini
apc.filters = wp-cache-config apc.filters = wp-cache-base apc.include_once_override = 0
Which corrected all of the Fatal Zend errors, but I was still getting an encoding error on every 10th page load or so.
After deleting the plugin, those went away as well. Since I found numerous complaints on the web about these two problems, I just decided to delete the plugin and try another.