I've messed around with all the styles a little bit. I love Path of Silence, since it feels like a true ninja sprinting everywhere and not leaving a mess. Path of the Hunter is okay, but I feel it doesn't have any actual advantages over the default (flares are really useful and smoke bombs are very strong as well, while I don't see the point in two kill items since the big point of them is range). Path of Might is utterly terrible as is obvious by the fact that you can't even use its advantages without getting alarms. And then there's path of Nightmares.
Path of Nightmares is comedy mode. This is the choice you pick when you want to beat the game by throwing bodies into the center of a brightly lit room through a vent in the ceiling and leaving while you rack up friendly fire deaths for all but one enemy in it. If you don't get a kill off the first round of fire, your darts have been turned into effectively lethal weapons since they mark enemies for their allies to shoot at. Every time a body falls to friendly fire, it's a whole new round of panic shooting because the guards will now terrorize themselves for you. Guards seem to forget how to sound the alarm over finding bodies in this mode (I've never even seen terror wear off), so that's a plus too.
At the end of the catacombs in the survival room with the slowly opening hatch, I made a single stealth kill and hid. I believe I got no less than 15, possibly more, kills just by standing there. (Although I actually died once due to not know that random gunfire will hit you in hiding spots--even those background doorways that appear out of the line of fire.) It's just too funny watching guard after guard panic as they find the guy their friend just shot, then shoot at the source of every sound they hear--the most common sound being the sound of other guards shooting, marking themselves for death.
"That is why war is so tragic. To win means to make victims of your opponents and give birth to hatred." - Kratos Aurion, Tales of Symphonia
Agreed, its great when there arent a lot of grapple points around or just for fun. Grim Harbinger is one of my favorite skills as well. (i do wish it worked better on elites, they interrupt my friendly fire chainkill lulzfest, but its already ridiculous enough i guess)
Silence is fun, but i prefer using it on levels ive already beaten. (which is most of them at this point)
Hunter is deceptively easy, after using it i sometimes forget that the QTE for stealth kill exists, 2x attack items is obviously fun too. I use my kunai/sound/visual range a lot for distraction so its a manageable loss, the 2 attack items open up some fun possibilities.
Might... Ugh, maybes its because i havent gotten the combat upgrades, but i fail to see it bringing anything significant to the table.