Eirik Hoem has
posted some of his thoughts on why the CodeGear software package
Delphi for PHP should have gone with the
Prado framework instead of their current choice,
VCL4PHP.
This kind of tool is something that ASP.net has had for a long time (ie Visual Studio.net). Not only does it make the development process easier when it comes to building applications, but it also handles setup of applications, default configs etc. [...] My impression is that most PHP developers (at least above hobby level) works on Linux based workstations, so I imagine getting a strong user base could prove to be difficult.
That said, he
has his reasons for why Prado should have been the framework of choice including the exception handling gap between the two (Prado on top), validation controls, how they use global variables and the rendering of HTML/XHTML by each.
Eirik Hoem's Blog: Why Delphi for PHP should have used Prado instead of VCL - Read More... 
