Tags and keywords
Manipulate for Graphical User Interfaces (GUIs) is good!
Mathematica's Manipulate is a dream come true, and is mostly easy to use, but there are some "gotchas" when developing very complex GUIs. The Webel ManGUI` package makes rapid development of Manipulate GUIs with uniform controls with informative mouse-over Tooltips and control layouts even easier. And it integrates with the Webel '$opt$' options system, too.
Webel IT Australia has developed substantial Graphical User Interfaces (GUIs) for complex engineering projects using Manipulate (and Dynamic) and also offers as a service development of desktop GUIs encapsulating Mathematica-driven solutions for end users for deployment to Mathematica or the cost-effective Wolfram Player Pro (which runs on most operating systems):