I have not been denied but yes they look into your past and most likely the past of your family. Having someone associated with you convicted of crime probably does not look good on you. But I could not tell you what the cutoff point is if someone had or a famaily member had past discretions with the law. Just remember they want to issue as many Sentri as possible but if there is any hint that you might be a risk then you will be denied. As far as it taking longer than your friend I know people have been waiting for 3 to 4 months to get a conditional approval notice. If you are in fact denied I believe you can setup an interview to ask why since I do not think that will be explained to you on GOES. Good luck.
Two to four months seems to be the average. At least, on line you can keep up with the process and they are quick to answer any questions you have aboutt he process with the online link.