I'm curious about this too and am interested to read any input. My son is NROTC (current sophomore at MIT) and also wants to go subs (as do the bulk of students from that battalion in any given year). He also wants to commit early because (from what he's told me) it also kind of guarantees that he can get an additional sub cruise his firstie summer. I guess I feel like he'd be better waiting just in case his cruise that summer (on whatever kind of ship) changes his mind (either that he doesn't like subs or likes something else more). Incidentally, he's a Chem Engr major and I don't think any of his (NROTC) classmates are Nuclear Engineering, even those who want subs.