I've been keeping marines for the last 18 months or so and they are no more difficult than tropicals to keep although it does require careful monitoring of the water conditions.
Personally i find that it makes me more vigilant than i used to be when i kept tropicals because it's always on my mind how expensive the fish are should i neglect it.
With the modern equipment available these days it's really quite easy to keep marines but make sure you do your homework and fully understand how a tank cycles and the importance of live rock in the aquarium, also don't overstock the tank with fish, makes it much harder to maintain the correct water conditions.
Personally i find that it makes me more vigilant than i used to be when i kept tropicals because it's always on my mind how expensive the fish are should i neglect it.
With the modern equipment available these days it's really quite easy to keep marines but make sure you do your homework and fully understand how a tank cycles and the importance of live rock in the aquarium, also don't overstock the tank with fish, makes it much harder to maintain the correct water conditions.