I like most how easy to use, fast servers are set up for my domains! The support team has always been very efficient in answering our questions or helping us fix any issue we've encountered so far.
There's nothing really bad about this service, but they could improve their billing process as it can be confusing at times when you're trying to pay your bill (or have an invoice sent). Great option if you want one-stop shop where all of your DNS needs will eventually fall under one roof including hosting. The service has been reliable, fast to respond when there are problems or questions about our sites' performance! There isn't much I dislike at this point but maybe they should provide better support for their free DNS hosting offerings? We've had great success using them as part of an overall CDN+PaaS infrastructure which we use across multiple projects/companies (and have integrated into other products).