I'm not really qualified to talk about JavaFX, since I honestly don't know very much about it. But my understanding is that its restricted to only running on computers that have the Java Runtime installed. This has historically been a sticking point with widely deploying Java, as its penetration is low in comparison to Flash or DHTML.
Laszlo applications can execute on both the Flash and DHTML platforms. In addition, there is the Sun's Project Orbit that allows Laszlo applications to run on J2ME.
I see that many companies use Laszlo, I was wrong. I have a doubt: what's the difference between Laszlo and OpenLaszlo?
Joined: Jan 22, 2008
There is no difference between Laszlo and OpenLaszlo. The name of the company is Laszlo Systems and when their Laszlo server became open source, it was renamed to OpenLaszlo (which I think is a bit of a mouthful).
RIA development is a huge new area of development, so it doesn't really make sense to ask which language or system is better. Its like asking what is better Ruby or Python, where each language has its own group of dedicated developers. So I wouldn't try and pit Laszlo in competition against other systems like Ajax toolkits such as Ext.js. There is no universal solution to every problem and there are undoubtedly many situations where Ext.js is the superior solution and the same for Laszlo.
But Laszlo does include unique programming methodologies, so if you really want to understand RIA development, then I think a working knowledge of Laszlo is mandatory.