Honestly, the easiest coral I have ever tried to grow is my red montipora capricornus (stony coral). It's practically bullet proof in nearly every light/flow combination I've put it through. The other stony corals are best left alone right now IMO.
You'll probably find that your individual tank will grow different corals better than others. Why? Almost impossible to say, but i've read a lot on this site and it just seems that some set-ups are better for certain corals than others. For example, Anthony said Xenias "aren't as easy" but in my tank they are just about impossible to kill. GSP on the other hand, will not grow for me. It's crazy, just won't grow, and has been steadily receding in fact. I have zoas, a gorgonian (type of soft coral), and multiple species of stony coral living and growing (albeit slowly) in my tank, but GSP will not grow, lol.