Ajax vs. XML UI Language (XUL) Toolkits

Hello,

   Jep Castelein writes:

    I don't think competitive differentiation was discussed on this  
list before, and I haven't seen many good posts about this on the web. I
don't have a complete overview, but below is a quick brain dump, and  
maybe others can add to it.

Just to clarify my position: I work at Backbase, a commercial AJAX  
toolkit vendor. I keep in touch with Alex, and we don't see Dojo and
Backbase as head-on competitors: obviously Backbase focuses more on  
commercial users, who also require support, etc.

Possibly the easiest way for diffentiation is the client technology

- AJAX: HTML, CSS, JavaScript (Dojo / Ruby-on-Rails / Backbase)
- Flex / Laszlo: Flash
- XUL / XAML: fat client
- Nexaweb / Canoo: Java applet

The benefit of AJAX is that it's zero install, although Flash isn't  
doing bad either (80-90%). XUL requires a Mozilla browser, and XAML a
future Windows update. A JVM is not installed by default any more on  
Windows machines. Anything that needs to be installed can be a problem
for less advanced users, users who just don't bother, or for  
companies with a lock-down policy for workstations.

  From a developer's perspective: developers usually like to work  
with technology they know: HTML is known very well. Flash is mainly  
known by
artists instead of programmers (ok, that somewhat exaggerated

.
People with a Microsoft background typically like XAML, and Java- 
developers (especially with Swing experience) are often attracted
to Nexaweb/Cannoo. I think this is also why people are excited about  
Ruby-on-Rails: it is bridging the gap between a server framework, and
AJAX client technology. At Backbase we're also bridging this same gap  
by introducing a .NET and Java version of our product.

Download size can also be important. Flex is a 120Kb initial  
download, Laszlo something like 250Kb, Canoo something like 400Kb,  
while AJAX is
much smaller. E.g. the Backbase initial download is 28Kb (munched).

The main objection we hear from people about AJAX is 'death by a  
thousand cuts': they mean that browsers have so many quirks, that it's
nearly impossible to develop and maintain stable AJAX applications.  
Of course, this is the problem that AJAX toolkits aim to solve.

I hope this is some useful information. If not, please ignore. If  
yes, feel free to correct my possible mistakes or add to it

Thanks,
Jep

    Any thoughts? Any comments?

    - Gerald