I've checked threads started by you... 2 pages worth of threads, none of which I could find talking about PPL advantage. My short experiences have shown me that a private pilot's license with instrument rating will improve your performance during flight school. Much more than that, and you'll be re-training bad civilian habits. As for COMPETITIVENESS, prior flight experience has virtually NO effect on your application. That is mostly an air force thing. So if you want to post a link referencing what you're talking about, great. Until then, I contend that having ratings will have VERY little impact on a candidate's competitiveness.
I'm tired of hearing the re-training bad civilian habits BS. The following refers to Primary... The Navy tells you EXACTLY how they want you to do things and there are acronyms for EVERYTHING. The differences are minor. I don't remember a single time in primary where I thought, "oh my god, this is completely different from everything I learned." In fact, most of the time the little differences made more sense and were an easier way of doing things. If you are too much of a retard to study and learn the way they want you to do things then that has nothing to do with your training. It has to do with you.
With respect to prior flight time... a PPL alone is not much more training that IFS. All things being EQUAL on an application the private certificate could give you a leg up over another guy. Instrument rating (being one of the hardest things to learn in primary) would help even more. Some of these instances where Joe Blow didn't have flight time and he got selected over me can probably be chocked up to other things on the application (GPA, test scores, etc.). The bottom line is any amount of experience will help you when it comes to primary. Why do you think they instituted IFS? However, just because you have prior flight time doesn't mean you can blow off studying. You still have to know your shit. The majority of your grades come from how you perform in the aircraft, and if you are more comfortable flying because of that experience AND you know your procedures you should do just fine.
"I have flown in just about everything, with all kinds of pilots in all parts of the world — British, French, Pakistani, Iranian, Japanese, Chinese — and there wasn't a dime's worth of difference between any of them except for one unchanging, certain fact: the best, most skillful pilot has the most experience."
— Chuck Yeager
Prior flight time is an all encompassing term that groups everyone into one pool. However, there are differences in pilots and there are differences in schools. There is the guy who went to Uncle Bob's flight school and got absolute dog crap training yet still got his PPL. Then there are people that went to reputable schools, and got great training. There are good and bad pilots at both. From what I have seen the guys who were trained to be professional civilian pilots, the guys who went through and completed a regimented training syllabus, tend to do very well in training. Of course, there are always a few outliers. So... if you sucked during your civilian training, then you will probably suck in Navy flight training as well.
To the OP: I don't believe the prior flight time would offset your DUI. As someone else said, LOR's would probably help you more in that department. But the prior flight time WON'T hurt you. Do everything you can to put together a strong package and hopefully things will work out for you. Good luck.