First off, I recommend going to
http://www.goniopora.org and reading through all the information on there that John Kelly has to offer.
Goniopora are slowly becoming easier to care for in captivity. Personally, I've had mine for just a bit over a year now and they are doing well. They do require almost daily care/feedings though, much like a Sun Coral does.
Like anything, certain species are more delicate than others, with the general rule being that the smaller the polyp, the easier it is. In general, the green goniopora are the most delicate and unfortunately are the ones most offered in the hobby.
Usually, the demise of these corals is created by one or two different factors. The first being starvation, and the second being brown jelly infection. There is a large misconception that these corals are okay to be in the sand, although most, if not all of them are found on rockwork. When the tissue gets abraided by the sand, it gets infected with brown jelly and it is usually too late to do anything by the time the infection is seen.
Being a newbie, I would suggest waiting at least 6 months to a year before attempting these corals. They like pristine water conditions, much like SPS.