This is perfect for preprod environments. I'd probably not deploy in production. There is a better nat instance setup available called alternat [1] which is a little more durable and better for production cases.
The longer term vision for fck-nat is a two node approach using conntrackd and keepalived to actively failover existing connections to the secondary with no loss of availability. This has the added benefit of not requiring all of the auxiliary infrastructure that Alternat sets up.