Thanks for the feedback. This is a great community. I would love to have more examples on the site. I have included a fully functional Java client on the code page, and will be looking at Objective-C/Swift as well as your suggestion for JavaScript. Asynchronous-response-capable and HTTPS is the basic requirement...if the XHR works I will post the examples on the site.
Regarding comparisons, the DropFrog emphasis is ephemeral messaging--the API is all about communication/messaging between the connected clients and when there are no more channel participants, the channel is destroyed. I have also toyed with the idea of adding limited persistent storage capability; will be listening to feedback.
The pricing is rock bottom, but designed to be sustainable with the current feature set.