USCGA is a much smaller SA and the USCG a much smaller service. The missions upon graduation are very different. From USNA, you will serve on (generally) large combatant ships, drive subs, fly jets (in some cases helos or props but mostly different missions than USCG) or go into the USMC. I'll let LITS amplify, but USCG does drug interdiction, buoy maintenance, ice breaking, maritime support, rescue, etc. I suspect (but don't actually know) that you might get more immediate opportunities for leadership in the USCG because the ships/units tend to be smaller. But if your desire is to fly jets off carriers or be a SEAL, then USCG isn't going to be your thing.
I had to decide between the two SAs years ago. At that time (when combat opportunities in the USN were non-existent for women), I preferred the missions of USCG officers over what I could do in the USN. That said, I ultimately chose USNA because of its size -- for me personally, coming from a very small high school, I wanted a school where I didn't know everyone and that offered the opportunities in terms of majors, facilities, etc. of a larger school. But that was only my decision made by a 17-yr-old in a different world years ago. I don't regret it but also believe I could have been very happy in the USCG.
Correct. On the aviation side the Coast Guard is much more limited. There are a few fixed wings (planes) to chose from and two kinds of helicopters. With the exception of the Coast Guard in Washington, D.C., and HITRON (Helicopter Interdiction Tactical Squadron of our Jacksonville, Fla.), Coast Guard aviation is typically involved with Search and Rescue (SAR).
Afloat there are three general ship missions, although these is quite a bit overlap. Red hull cutters break ice. Black hull cutters are mostly engaged in Aids to Navigation (ATON) which usna1985 called "buoy maintenance." White hulls do everything else.... SAR, drug interdiction, migrant ops, homeland security, etc. These cutters range from 87' Marine Protector class cutters to the 420' Healy class cutter.
You WILL get more leadership opportunities early in your career in the Coast Guard. You also have more jobs (collateral duties) and responsibility. I didn't realize how much more until I went to a Navy school and discovered what my classmates, Navy junior officers, had to do.
BUT the Coast Guard is smaller... as are the units. You could have a commander or captain (although the captain would likely be transferring out shortly) on a 210' Reliance class cutter moored up next to a 500+' destroyer with the same ranked commanding officer.
While you will have more responsibility earlier on, you'll never be the CO of a aircraft carrier. With the exception of a few flag officers and captains, you'll never been in charge of thousands and thousands of people.
But the Coast Guard is pretty good at what it does, and it's a small, tight group. And the Coast Guard Academy (and alumni network) is even tighter.
Where could the Coast Guard improve? Well, it could have better funding and better ships, but the Coast Guard doesn't always help itself out in this department. It tends to run its ships to pieces. There isn't a defense contracting presence pushing Congressman for the Coast Guard the same way you might see in the more expensive, bigger services.
In the end, I'm happy I went to the Coast Guard Academy. I'm served in the Coast Guard. And I'm happy I've moved on to other opportunities.