Looks like a solid list, plus also unique as it is not the "usual" HE list that you see from most players. And as to how you should run your Marines, I would probably say either the Phoenix Guard or the White Lions. Swordmasters just die in droves very easily and usually very few of them make it into combat, hence why I think in this case they wont be a good choice. Leaning with the Phoenix Guard, as not only do the give you a respectable S4, but also have the great 4+ ward save, and backed up with a Lvl. 4 Shadow mage with the book of Hoeth will make this unit deadly.