My husband got out of the military about 4 years ago after serving 6....I definitely understand where you're coming from because it was an extremely nervous time for us...he got out in 2009 when the job/real estate market was still rather crummy.
First off, thanks for your service
Giving up 4 years of your life to serve our country is something to truly be proud of. That being said, don't spend the next 16 years of your life miserable in a job that doesn't fulfill you. If you do plan on merging into the civilian world, try to start interviewing for jobs while on terminal leave or a few months before your contract is up. There are many military friendly employers around the country who would consider you an asset!
Re: MBA - most companies offer tuition reimbursement.....with all that's going on with military tuition right now (not paying for active duty members to attend school), you might have better luck in the civilian world.