Software Engineering vs. Systems Engineering?

An anonymous reader asks: "I recently graduated with a master's degree in computer engineering. I am currently a software engineer for a defense contractor. They (same company) have now offered me a position as a systems engineer. Any advice? What are the long and short term ramifications of the change, in respect to job duties, advancement, compensation? I am pretty much fresh out of college, with only a year of co-op experience. I am a little over whelmed by the choice with no experience to go by, but I also don't want to pass up a great opportunity. Thanks for the help."