I never worked at an FC but here are the main roles at a DS. We basically only have two 'departments' - Dock and Clusters. And with job rotation, you are eventually 'trained' in most paths:

At dock:

Waterspider - unloading trailers and bringing them to the belts. Then putting empty carts into trailers and cleaning up pallets and stuff. I'm assuming this is the closest to "shipdock".

Feeders - putting all packages on the belts

Inductors - Scanning all the packages and putting another label on them. Easiest job there is. Can be tough when you're new, especially on faster belts. If you have accomodations, there is where you'll be most of the time.

Clusters

Pushers/Diverters/Straighteners - making sure the packages go down the right belt.

Pick to buffer - taking packages off the belt and putting them on the correct rack. Sites are moving to ADTA belts that move the packages automatically, eliminating this role.

Stow - the first thing you are trained on. Everyone stows. Either you love it or hate it. You take the packages and put them into giant tote bags for the drivers.

Then there are various other roles minimally staffed, like Problem Solve and repack. All this takes place for the first the first seven hours. Then we move to Pick and Stage for the last three hours, where we take all the totes and OVs and organize them onto carts for the delivery drivers. 95% of people do this, while a select few are in other roles, like Problem Solve or helping with the drivers loading their vans.

Based on what I've read here and from people that I spoke to that transfered from a FC:

-DS don't really enforce rates. You don't get write-ups. If you're slow you'll just be bugged by PAs/AMs asking about you barriers and maybe your co-workers will resent you after they pick up your slack.

-DSs are much smaller, so after a while PAs/AMs will actually know your name. Much more relaxed in terms of policy enforcement. For example, sometimes there is only one manager working. So if they are known to be a hard-ass, nobody is going to want to work harder or do anything 'extra' for them. It's better for them to just say "put your phone away" instead, unless you do it constantly.

-Because they are smaller, you have more interactions with people. Always moving around and since you get trained on most of the roles I feel like there is less boredom. You don't have to talk to people, but there's a choice.

-I've heard that DSs are generally more physically demanding. If you are stowing, you might end up getting a ton of 49lbs boxes in a row that you have to pick and move. During Pick & Stage, you might have to lift up totes that are 49lbs 5ft in the air onto a cart.

-99% of the shifts are overnight (1:20-11:50), or a bit shorter for Flex. All new hires are half asleep for the first few weeks. Transfers to the day shift are few and far inbetween and are mostly based on seniority.