pfSense

Suggest default to off

Description of feature here, its pretty killer.

serve-expired: <yes or no>
If enabled, unbound attempts to serve old responses from cache
with a TTL of 0 in the response without waiting for the actual
resolution to finish. The actual resolution answer ends up in
the cache later on. Default is "no".>

I also have a few other guys testing this as well including martin, no negative feedback so far (we testing via adding to custom options box).