I like that it's easy to setup with minimal configuration required. It worked great out of box as well! The only thing i disliked was sometimes when we were receiving emails from our clients they would show up in spam folder due to DKIM not being configured properly (which made me feel bad). We needed an affordable way to handle multiple domains but still wanted some control over them. This solved all my problems. Also we had another service which did load balancing using HAProxy but at times there could have been better performance. Now we are running everything through GSLB.me which has really improved the overall performance of our website.