It is hard to say because the number of applicants are so different. But no, there does not seem to be an advantage as far as the acception rates go. However, there often seems to be the benfit of more/better LOR's. Also, FITREPS are likely to be much easier to evaluate for the board than civi resumes. That can be both good and bad depending if you excelled or if you were just average/slightly above average.
Chances are pretty much up in the air. Having an average/above average GPA and ASTB helps, but the other parts (moto statement, LORS, interviews) play such a big part it is hard to guess. As you will see on here often, if you get a no, improve and try again. Its the best way to look at it. Always be improving so that you can show consistency.