Will OCS or ROTC be better for me?

OCS selection is quiet competitive. It would be more of a sure thing to contract with ROTC. Also, with ROTC you usually get very good grades and it helps pump up your GPA. And frankly, ROTC is much less intense than OCS.

There are a number of factors, that when combined, will make you competitive for the 72D selection board. Note: you can only commission 72D in two ways: as a biology or environmental major attending Westpoint, or by having experience/credentials, and applying through a Direct Commission package (via an Army Medical Recruiter). They recruit about 20 per year, with 10 coming from Westpoint, and the rest through Direct Commission selection boards. The DC route is highly competitive, with about 150 applicants per year for 9-11 positions (on average). The people selected usually have direct civilian or military environmental and/or public health experience, and a qualifying degree. People with a qualifying degree and no experience are the least competitive. Note: I was selected in October 2018, and just went through the process.
Academics: Having a BS/BA (or higher) in an environmental discipline is the cornerstone to being competitive. Personally, I earned a BS in Environmental Health. A key thing to note (this comes directly from the 72D Consultant): 45 semester hours must be a combination of science and math courses (any combination). Course titles like geology, botany, biology, epidemiology, environmental science, etc., all count towards adding up to 45.
Certification/Licenses: Personally, I had already earned a state-level license as a Registered Environmental Health Specialist, and had the Dept. of Defense Pest Management Applicators License (ties into disease vector control). Any kind of public health, environmental, or related professional certification increases your competitiveness.
Letters of Recommendation: You must have at least 3, but you can have up to 5. At least 3 of my letters were from Lt. Col’s or higher, and 2 were from my academic program. Definitely aim for 5 letters from people that matter. The "higher up" your letters are, the better. For example, a letter from your environmental science department head and/or program director is stronger than a regular associate professor on staff.
Military/Civilian Experience: In general, being prior service is a huge plus. Likewise, having completed service schools (NCO Academy, etc), are a plus. If you already work in military health, that will give you a slight edge, especially if your MOS is related to 68S or another preventive medicine or veterinary corps MOS. Likewise, civilian experience in an environmental or public health field makes you highly competitive.
Volunteer Experience: For 4 years, I volunteered as a merit badge instructor for the Boy Scouts, teaching the Environmental Science Badge, and the Public Health Badge. Doing this in your free time really communicates to the selection board that you embody the 72D MOS.
To conclude, all of these factors combined is what got me selected, and definitely made competing much easier. Good luck.

You don’t need OCS or ROTC to become a 72D ESEO. With your degree, look for an AMEDD Officer Recruiter in the major city of your state. Ask them about Direct Commission after you complete your degree.

https://www.usphs.gov/profession/environmental/

Trust !e, this would be well worth your ti!e to look through, also....

Prior to OCS I was told by graduates that OCS would be 3x tougher than any other commissioning source and, indeed it was tough; it was the condensed Military Science portion of the USMA and it was highly competitive to enter and to maintain your place till graduation. Therefore; I suggest ROTC is a much better option and an easier avenue.

Thanks.

https://www.gocoastguard.com/about-the-coast-guard/discover-our-roles-missions/marine-environmental-protection

You'll want to look at this also....

https://www.glassdoor.com/Salary/US-Army-Corps-of-Engineers-Environmental-Scientist-Salaries-E41319_D_KO27,50.htm

This is civil service, however, it's at least illustrative...

https://en.m.wikipedia.org/wiki/NOAA_Commissioned_Officer_Corps

Look at this as well in detail...

https://www.gocoastguard.com/active-duty-careers/officer-opportunities/programs/direct-commission-engineer-dce

And this...

https://www.gocoastguard.com/active-duty-careers/officer-opportunities/programs/direct-commission-programs

Look at this as well...