I set up my saltwater about a year ago and the biggest difference I see is money. Lighting is definitely a key element and something you don't want to skimp on. 4 watts per gallon should allow you to keep just about anything. Even if you don't want coral, the lighting will allow your live rock to grow coralline algae. The live rock makes a big difference, as the algae, which will be purple, red, etc and the organisms that live in it will really aid your filtration. You probably want at minimum a half pound of live rock per gallon. Live sand will do the same and the combination of rock and sand will really speed up your cycle time. A protein skimmer is the only other real essential and I would not skimp on this either. With a smaller tank you may not need any additonal filtration than the skimmer and live rock. Larger tanks will probably need wet/dry or canister. After initial setup, I really don't see any difference. You might scrape a little more algae, but I find the water does not degrade as quickly. Don't cycle with damsels either. They will dominate your tank and make it tough to add others. Tankraised damsels, although also technically a damsel, should be hardy enough to cycle the tank.