IdeaMachines prefers, but doesn't require, Telelogics' Rhapsody as the UML2.0, SysML, DoDAF development environment for our Security Framework. Below are our reasons for this choice.

While preferring Telelogics' Rhapsody, with its Harmony and DoDAF support, we would certainly consider developing applications for a client using another framework. Our world is partly embedded, and Rhapsody has particularly strong support for the C language, still the most prevalent language in the embedded device space.  But  UML conformance means that object module diagrams, state diagrams, sequence diagrams, software and system descriptions generated with one vendor's framework can be moved to another framework relatively easily. 

Rhapsody is also the framework chosen by most strategic aircraft developers in the US for development of the airframe, communications, and weapons system controls. 

Action Language: Because we deal with a variety of embedded devices, we find the ability to write "methods" in "C", or, if need be, in SystemC, or VHDL, important.  Telelogic support for objects, attributes and activities expressed in the C is the best we have seen - by far.  We also know we can depend upon Telelogic to remain at the leading edge of modeling language development, indeed, lead the development of evolving standards such as graphical action languages and "virtual" real time kernels.

Ease of use: No one claims the UML is easy to learn.  It is claimed that the evolution to object oriented programming, the objectivization of C in C++, with some simplification in Java, has been relatively little used - few programmers design with objects.  Programmers use objects as containers for functions and data structures because the compiler requires it, but few explicitly use classes and objects, inheritance, polymorphism, as essential design elements.  The UML and Rhapsody will be an introduction for many to true object oriented design. It also provides, remarkably, for the reflection of changes made directly in procedural source code (C, C++, Java, ADA), to changes in the UML classes and associations. We are looking less-and-less at procedural (C, C++, Java) code and trusting the syntax checking and successful execution to validate the logic.

DoDAF: DoDAF, The Department of Defense Architecture Framework has turned out to be useful beyond its obvious application in DoD projects.  To model a solution, and then use Reporter+ to spit out a remarkably coherent document with a few clicks on pull down menus, including all the diagrams of all the views, is a pleasure to most of us who dread the production or, at least, reviewing of accompanying paper documentation.  Again, the Telelogic implementation is clear, and includes an excellent tutorial.

IdeaMachines Personal Experience with Rhapsody: With more decades of embedded and acquisition system design than we like to think about, IdeaMachines engineers are critical and opinionated.  Our experience with Rhapsody should not be so different from that of other engineers.  We have used mature and "bulletproof" development tools, and we have been involved with leading-edge technologies.  We are conservative developers as befits our industry, but admire the speed of "hack and build" programmers.  Rhapsody seems to bridge the worlds of rigor, state machines, hard determinism, and the rapid try-build-debug programmer.  Every major or minor Telelogic release adds features which don't don't break existing models, and enhance the efficiency of development.  Using Rhapsody is a process of discovery, but one which has allowed us to build robust models while still clearly novices with the UML.  Unlike processor oriented procedural development tools, learning the tool involves learning more about structures in the problem domain, as opposed to learning some clever keystroke combinations which may save time, but not improve the product.  And, unlike some very well known development frameworks, everything we try has worked!