Edsiaren Ignacio: I have wrestled with this decision recently and am almost 100% sure I will be getting out when my contract is up in 2 years.
My situation may be slightly different in that I have a degree in a highly desirable field that I can fall back on if needed. I also have no children and have already accumulated nearly a dozen units already.
I agree with Matt Devincenzo that compared to the passive real estate income you can develop in 17 years, the military pension fails in comparison. Have you done the math? Play around with this calculator and look at the different scenarios regarding your pension. See what happens if you make E-6, E-7, E-8, or maybe even E-9. Check out the O3-E, or O-4 retirements in case you end up going officer route.
http://militarypay.defense.gov/mpcalcs/Calculators/FinalPayHigh3.aspx
For what it's worth, an O5 who retires today with 20 years will take home only $2,630/month after taxes. Factor in inflation (and the fact that our annual pay raises are sometimes less than inflation) and that amount of $$ is almost laughable, in my opinion. Then again, the health benefits are worth taking into consideration, also.
I've written about this exact topic in my personal blog if you care to check it out, the link is in my sig.
Also, I see that you're nearby. Hit me up sometime and we can talk more about it. In the end a lot of it boils down to what you enjoy doing. If the military isn't it then I would suggest looking elsewhere. I would recommend taking advantage of the education programs the military has while your in.
Hope this helps,
Glenn
PS. I'm tagging James Vermillion in this post as he's a veteran who recently got out. Maybe he has some insight.