The practice test is more for your immediate recruiter than you, if I'm being 100 percent honest. It lets them know roughly what kind of jobs would be in your bracket.
The scoring for the tester though can be all over the place. I remember doing 'okay' on my practice test, then breezing through the actual thing. The big thing to take away from it is that you don't do poorly. If you do bad, STOP. Focus on getting yourself comfortable with the test and google whatever resources you can find to increase your score. Too often smart (and just average) guys screw themselves over by just rolling with where they stand and short changing themselves. If you do bad or simply think you can do better, then make that your goal before talking jobs and contracts with your recruiter. You lose if you do that.
Also, nothing against the other branches - but the Army's contracts will actually guarantee you the job whereas other branches give what's basically a soft commitment that you'll get the job you're wanting. Something to keep in mind.
