My daughter went to SLDCA last year, she loved it and learned a lot from it. She was Alpha Company, First Platoon, Platoon Sergeant. It helped her feel more confident, and taught her to keep her head in order under external pressure. Her MC JROTC instructors told me that her good boards became excellent after that summer.
SLDCA alone did not stand out on her high school resume. What stood out was that she went to out of state military camps, did volunteer work and participated in school MC JROTC camps every summer since eighth grade year. Her senior summer, when most of her friends were going on vacation trips, working part time or going to the beach, she went to four straight weeks of Military camps out of state, in addition to two weeks of MCJROTC camp at school, training a platoon of Young Marines and taking two summer school courses. She spent two weeks in Oregon for Young Marines Advanced Leadership School, flew into Connecticut for a week at the Coast Guard Academy for AIM, I picked her up in CT, and drove her to Virginia. She had a night to sleep, wash underclothing, dump that, her hygiene kit and sneakers into a prepacked sea bag and get dropped off at the Marine Corps Museum.
In her interviews, one of the things that was commented on the most was the number of summer things she did, as well as after school activities. The fact that SLDCA was the LAST camp in the four weeks seemed to weigh heavily in her favor.
The thing I personally find amusing about SLDCA is that she keeps complaining that the distance between the bars on the monkey bars were too far apart for a 5'4" female, even when she was swinging her body to reach. She ended up going to the end to do pull-ups.