I like that it's cross-browser, simple to use with all my browsers (chrome/firefox). There aren't many free themes available out there so you're stuck using its standard white theme which can be very bland looking if your trying to build something visually interesting! Also some of their icons are hardcoded but other than those minor things i think this tool has been great as most people already know how easy js alerts work from websites they visit daily - no need explaining what they do at first view. It makes me feel more secure knowing someone else was making sure any code could not exploit security flaws in our web site through an alert or pop up window box appearing randomly when browsing pages we don't want them to see. AlertifyJs is a very good tool to use if you are serious about notifications. A bit of a learning curve when you first get started, however, the support team is great and is always available to help. I have been using AlertifyJs for several years and have found it to be a great tool. I would highly recommend this tool if you are serious about notifications. It allows me to send a notification to all users in my organization when a new ticket is created or when a user has logged on to my application.