What matters to you most?
If you want a short stint in the military, either USNA or ROTC would work although they are light-years apart in your college experience. If you go to the USNA, you are literally in the military on a daily basis from Day 1, whereas if you are in ROTC you are technically in the military (if on scholarship) but your daily life is 95% that of a regular college student. Once out of the USNA or ROTC, your short stint in the Navy would be the same except for the fact that as an USNA alumnus, you have a large group of classmates starting/serving with you as well as a legion of alumni who will view you as a brother/sister because of your shared academy experience. If you decide to stay longer in the Navy, you will find being an Annapolis graduate carries many advantages. If you only serve your initial term, it won’t matter much which route you took.
If prestige of your alma mater is very important, it is arguably a draw among those three depending on the audience. People are usually impressed with an Ivy pedigree, but it will surprise you how many people don’t really know about schools other than HYPS, if even knowing the PS of that quartet. On the other hand, EVERYONE knows, understands, and has an opinion on the service academies. As a Wall Street banker at age 40, the differences may not matter and you are more likely to find fellow Ivy alums in your circle. As a business consultant in the Midwest at age 40, my bet is the USNA degree will mean more. Last, if you go into a crowd of random people outside of the executive business “class” anywhere in the country, however, people will shake your hand and nod approvingly when you say you went to the USNA, whereas half the crowd wouldn’t know Dartmouth from Denison from DePaul.
If getting an education preparing you for a specific area of business (like finance) is your highest priority, the USNA will give you a well-rounded education of top quality, but won’t even come close to the focused business training you could get at Dartmouth or Cornell. Your five-year stint in the Navy, however, may very well be a far better and demanding working experience than the job you otherwise would get in the business world at ages 22-27. What young military officers are asked to do dwarfs the responsibility of the average mid-twenty-something in the corporate world.
It sounds like I am advocating the USNA, but that choice has an asterisk the size of Texas–do you want, or even can you deal with, the daily rigor of an academy experience? Most people at age 18 do not want to spend 48 weeks a year (you only get a short summer break if you go to an academy, not a full summer off) going to a military boarding school rather than experience the freedoms of college life. I chose ROTC over an academy back in the day for that very reason, whereas for others the opposite choice would be a no-brainer. NO ONE can answer this question for you.