A lot of people will have different opinions based on career fields. Some require very different mindsets. I would probably be miserable in a mechanics or Security forces position. I don't like gums very much (target shooting is fine though) nor am I very hands-on mechanically.
So I joined the Intel field, and surrounded myself with friends and coworkers who for the most part are pretty nerdy like myself and often well educated. I have been in around 3 years and don't really have any major things I hate about my military life at the moment, though there are many ANNOYANCES, but that will be in every career.
What the military did was take me from making $9 an hour at a hospital with no education or prospects of advancement and give me a several hundred thousand dollar Arabic language training. It gave me an Associates in my language CCAF in my career and I am going to have a free bachelors degree soon. I am SrA making a gross income of over 60,000 (BAH + BAS + 12K a year in foreign language pay), it has saved me thousand of dollars in getting teeth fixed and I am planing to get PRK on my eyes soon as well, also free.
Most of all it has allowed me to join the Intel Community at a young age ( mid 20s ) and if I want I could very easily build on my skills and connections here with the NSA and make a life career here.
Depending on your finances and drive, you can probably be more successful in the civilian world in a shorter timeframe, but being in the military is probably one of the easiest and more stable ways to improve your life if you use all your benefits. You also end up putting back and helping a lot of people along the way, especially if you become a good SNCO or officer, you will touch the lives of hundreds of people in a possible way throughout your career, regardless of career field.
While the military can be a last resort for people, as SilentD said it is also changed now to have a huge focus on self improvement now, there are thousands of very educated and capable people you can network with and help each other build a good career and life.
It is not for failures, just be sure to research and know that you have to wade through some bullshit every year but for the most part it's been totally worth it for me.