I find it requires a bit more work than a fw
setup. Once youre up and running and everything stabilizes it does pretty much run itself. Weekly water changes, testing periodically, having a skimmer and keeping it clean, all stuff you gotta do. I happen to be running a canister filter on my 55g sw
right now so that's also an added maintenance item.
Are you wanting to keep corals or anything like that? or do you want fish only with live rock? That will help determine the cost and maintenance schedule.