Well, I honestly don't know much about GWT, and have not used it myself. My advice, with any technology, is to try it yourself and draw your own conclusions. Too many times, I've seen comparisons of one technology to the other that were biased, based on one person's (or group's) preferences, that I've always decided to try things myself. For instance, the C++ vs. Java argument that went on for years, Eclipse vs. NetBeans, Windows vs. Mac OS X, and now JavaFX vs. Flex, or SilverLight, or GWT, and so on. They all seem to have strengths and weeknesses and will appeal to different people differently. I like JavaFX because it's almost like an extension to Java, with a powerful language that makes it quick and easy to build GUIs, and runs on desktops and mobile devices alike. Let me know what you think after you've played with it. Try it at www.javafx.com
Cameron Wallace McKenzie
author and cow tipper
Video can only play on systems that support the specific codes. On Windows, JavaFX uses the Direct Show libraries so all the Windows codecs are supported, like Windows Media Format (WMF). On Mac, the Core Video is used, so any codec supported on Mac will play, like quicktime (.mov). The On2 format for JavaFX can play on all the platforms including Linux and Solaris.
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com