I like how NAR has more members. They offer competitions too. The NAR is a one time fee this is a major advantage to NAR and your cert never expires I think. They are respectful to student groups. I only felt shoe-horned into external wiring around a casing a MD multistage sustainer through NAR because they wanted rear ignition. TRA had more options in that regard. NAR rules felt more restrictive. Sorry I shouldn't have used the word snotty. They operate slightly different. NAR isn't bad for sport rockets. NAR seems way more family oriented. NAR is cool with bring your own launch pad tower.
From a student competition multistage perspective, NAR allows complex multistage MD rockets on certified commercial motors, no motor modifications, even altimeter deploy, but meeting the rearward ignition requirements complicates interstage design and tactics. The material restrictions were to comply with sport rocket class in the spirit of fiberglass or carbon fiber though most non metal structures apply. So in national competitions especially at university level, a team under Tripoli with an L-2 simply has more options for the same membership through organizational operating procedures at research launch dates. If you want to fly the hobby for fun with minimum hassle and expense then NAR is going to be hard to beat until you want to mix motors or change hardware.
For example, a student group with Tripoli under a research launch date can fly a motor modification with a new nozzle design to optimize thrust at an altitude by designing for back pressure at altitude for multistage sustainer or high elevation launches. You'll realize most commercial motor manufacturers have a drill hole at nozzle geometry as that was economically cheaper than making a new converging diverging nozzle for every single load, and they have designed it for a set altitude pressure not any close to what you want to do specifically. A group with NAR membership would have no luxury that I know about. These additional design features that students undertake in a simple scratch build rocket are worth more points in national engineering student competitions. Sorry to get too far off topic. Tripoli offered low cost student membership.