JROTC is an excellent program and since your school's program is an honor unit with distinction, you can count on it being good. You will get leadership experience in that program if you join that you will be able to use in your life whether you get a nomination out of it or not. Having just gone through this with my daughter, I understand your desire to have as many paths to nomination as possible. But, keep in mind that there are few JROTC/ROTC nomination slots and your chance of getting appointed on one is relatively low. Before you join, think about what you would not be able to do if you do join. Would you be cutting yourself off from a leadership position in another program? Are there other paths to show your leadership potential?
One benefit to joining is that you will have some access to an Army officer. They can help you better understand what that means and what it takes to succeed. That may be really useful.