Smallboy:
Lots of opportunities to step-up and take on assignments, but with smaller wardrooms, a bigger chance of being SWOd by another JO. You know all the crew. With fewer people, you stand more watches. We had the fewest duty sections so you had duty days more often than other ships. The CO on a FFGs and DDGs are first time command, which affects their views. DHs are LTs so they are closer to you, but again less experience to learn from. On our FFG (and I heard on DDGs) unpinned JOs slept in enlisted overflow (it was separate from berthing, but you are not in a stateroom) Okay, not a problem as you’re female, but you may get stuck sharing a room with a DH if they are the only other female officer. Port visits are fun. Because of the smaller ship, you can go to a wider verity of ports than the larger ships. However, if the larger ships enter the same port, your ship gets the leftovers. Except for CGs, the CO seniority is lower so other commands have priority preference (ie port visits, pier berthing, when they enter or leave port). My First XO (a shoe) stated that a smallboy emphasizes what it is to be a SWO.
Amphib (at least on an LPD):
Lots of opportunity, if less on the combat side (During wargames, our standing orders was to "run away". We use to joke that our most dangerous weapon was the rust we might infect them with if we made contact). Larger wardroom, shared with the Marines. I really enjoyed the Marines on my first boat, but I was one of the few who hung out with them. Lots of sailing in circles while deployed waiting just in case something happens and the Marines needed to go ashore. If your intent is to do four and out or get your pin and lateral transfer, Amphibs are stated to be the easiest to earn your SWO pin. Our boat had PQS training classes to help the JOs with their quals. We didn’t have that on the FFG, but that may be because of how many unpinned JOs we had onboard. Large staterooms for all officers (at least on the old Austin class) and often you can get a stateroom to yourself. I know one of the second tour JOs had an exercise bike in his stateroom and the Chaplin had a piano. Our deployments were longer than the FFG but we also spent less time in port (this could be a good thing or bad). If you like to PT, the gym is better (although packed when the Marines are on board). The atmosphere on the Amphib is slower and more relaxed (but still professional) than on a smallboy. Of the two boats I was on, I preferred the gator.
LCC:
The two JOs that I met on a LCC complained that it was a floating hotel with way too much brass. When they left homeport, they stated the port visits were good but more of shopping trips for the brass than anything. It wasn’t what they joined the Navy for.
USNS:
The three JOs that I worked with loved their tour. I’m not sure how its viewed career wise. Large and individual staterooms with personal heads (I think they said some else cleaned them but…) . Professional cooks with the best food so I heard. Working with civilian mariners who really know they stuff, so you can learn a lot about being a Sailor, but less on the combat aspect. They did complained that they spent more time at sea than the regular fleet, but it was mostly back and forth from port to strikegroup and back.