General
How does echo differ/compare with other web frameworks?
Echo2 does reduce bandwidth between browser and server. It does have to go through some hoops to figure out what has changed but the cost of that is much lower than what most web frameworks have to go through to constantly recreate objects and state to rerender the entire page every time the smallest thing changes on a page.
Echo2 can consume more session state than some other statless web frameworks, but that is up to the developer to control. With most other web frameworks the user is required to mange state. With echo2 the framework does it for you but the developer is responsible for keeping state to a minimum.
Memory/CPU and other requirements are probably not that much different than any other frameworks. It is really a function of how the product is used, how many concurrent users........etc. Echo2 session are sticky so load balancing requires session affinity across the appserver farm (if you need one).
echo2 works over SSL like any other html app. Security is no different either, in fact echo2 probably has better security than most other AJAX systems like openlazslo or bindows because it only renders the content to the browser, most of those others requires all the application to be dumped to the browser at once, which makes reverse engineering a bit easier by a hacker.
How is Echo2 licenced? Is it free?
Echo2, like its predecessor, is open-source software distributed under the terms of the Mozilla Public License (or, if preferred, the GNU LGPL License).
Is there a drag and drop design tool for echo2?
Yes, EchoStudio2 is an eclipse plugin that provides a fully functional IDE for developing Echo2 applications. EchoStudio2 is a commercial application and is optional. You can most certainly develop Echo2 apps without it. We'd love for you to buy it, but if you don't see it's usefulness, please don't feel compelled to do so. If you are interested but require a trial license period longer than thirty days, I'd be happy to generate a license key with an added month or two before it times out. In any case, feel free to just go download and play around with it now with the existing 30-day key without worrying about using up your trial period before you really get a chance to evaluate it.