data manegment

I want you to answer this question now.. in one paragraph with an example.

I'm a business manager of a large food processor plant and we need to apply a significant software upgrade to our business tools.  This is a major upgrade which will require a significant change to current tools.  I have hired you to organize a project plan associated with the upgrade.  Would you use a traditional SDLC (standard development life cycle) methodology or would you use an agile methodology?  Explain your reasons for your selection.