I have researched this topic and it does set you from the pack, since even a weekend warrior can get vet preference, being an officer shows that you have dedication, ability to multi-task, and have leadership. Those are strong qualities that yes even an E-5 can posses but at the O-level its a different set of standards.
Officers, atleast in the Marine Corps, are held to a higher standard then enlisted (but this is true with almost any branch) An Officer Candidate must have no criminal record, (or atleast no felonies) have a degree, higher pft score, more professional appearance (ie no visible tattoos) no medical history (such as asthma, bad vision etc) and testicular fortitude. OCC is not a walk in the park and has a high drop out rate. After OCC then you have TBS after TBS then you have your MOS school. You will be training for atleast 9 months before you get libo. So your not just a 90 day blunder. Your training is considerably longer then that. Also Combat Arms MOS's are highly competitive, so you cant just sign up for infantry you have to be selected. One of my good friends just got back from TBS and has to go to his MOS school in Sept after being away for 9 months.
On the enlisted side, these tend to be more lax and are more easily waived then for an officer candidate. Plus, boot camp is not nearly as tough as OCC. Unless you go to NG OCS and that's every weekend for about 2 years or something ridiculous like that.
Plus being an officer will help you more on the federal side if thats the route you want to go.
Since your only 20, you have some thinking to do. If your going to join up purely for vet status then go NG and do your one weekend a month or reserves. If you want to do more with your life and have the coveted responsibility of leading troops/marines/sailors into combat then become an officer in a combat arms MOS.