More and more clients are now IPv6 only (notably on mobile). If your service is only accessible through IPv4, the client will access it some kind of stateful eq

More and more clients are now IPv6 only (notably on mobile). If your service is only accessible through IPv4, the client will access it some kind of stateful equipments to do the conversion between IPv6 and IPv4. You are likely to get a small latency hit but also a lower reliability. As the bigger sites are IPv6 ready (Google/Facebook), the reliability of the translator equipment may not be the top priority.