I'm not familiar with the Sunfire compiler. I assume you are referring to the 'Sun One Studio' package, which includes a suite of compilers, C, C++, etc. Sun makes a series of servers called the 'Fire' series, which leads me to believe your confusion with 'Sunfire.'
If so, the Studio suite is rather expensive, approximately $3,000 USD. You can download an evaluation version, and if I remember correctly, it lasts for 30 days.
For more information:
http://wwws.sun.com/software/products/studio/index.html
As far as user friendly goes, it's like any other UNIX compiler suite, and should have similar arguments and flags. Most features you probably won't be using, such as the vast number of Sparc optimizations the suite supports.
If you're familiar with the GNU Compiler Collection, Sun Studio shouldn't be anything new, unless you plan on doing anything spectacular.
If you feel that you are unable to afford a license, or don't feel like playing with the evaluation version, I'd suggest installing the GNU Compiler Collection. If you're running any derivative of UNIX, or any free-deriviative UNIX, you'll need to check if you have 'gcc', 'g++,' etc. If not, you'll need to read the appropriate documentation for your OS and install the needed packages.
If you're using Windows, the solution is simple:
http://www.cygwin.com
Cygwin allows to run UNIX applications in Windows (they must be compiled in Cygwin, however). During the install, it'll ask you which packages you would like to install. Of course, install all the development tools, which will install the GNU Compiler Collection. Be sure to read any appropriate documentation.
If you'd like more solutions, I'll offer one more. I assume that since the Fire server will be using Sun Studio, you might be able to request a login (if you don't already have one) to the system, so you could use telnet or SSH and use the system remotely or a remote X session.
