what are the limits for 3d game studio with making simulationsDepends on how much work you want to put into scripting your simulation.
and can the graphics compete with comercial games today??? Depends on who you have on your team and what you're trying to accomplish. With a good team, you could create something comprable to most anything you could pick up in a game store. It's not as high-end as UT2003's engine, but then it's also older than UT2003's engine. A6, perhaps.
Mainly, you need to figure out what you're doing, the talents of your team, and then ask more specific questions.
A5's a great engine. There are better ones out there. In fact, depending on your project, there will always be a better engine out there...just not for your project.
Go here and read about the different upsides and downsides to this engine and others:
http://www.conitecserver.com/ubb/ultimatebb.php?ubb=forum;f=23
