Hi Suemt,
You need 2 years of experience to sit for the CMT credential but not the RMT credential. The RMT test was created for newbies and also for experienced MTs who do not have acute care experience (i.e., working in a hospital).
The RMT would give you an edge when looking for a job because getting that credential would show an employer that you have proven skills acquired in your transcription program. Transcription programs vary widely, and obtaining this certification would verify that you have the basic skills needed to be a competent MT.
If you want more information about the RMT or CMT, check out
www.ahdionline.org.