I played the Nazgul Battlehost in the final game at the WotR GT (on its way it beat a 5-foot-wraith/Gorgoroth Horde/Morannon list used by one of the previous LotR GT winners. Also destroyed a Grey Company/Aragorn/Dain/Elendil/Galadriel combo list in 45 minutes, as well as easily owned 2 other armies) - the battlehost is insanely strong. (you can check out my GT report in my signature).
But:
Shadowlord is a no-no, he's got nothing special, you're better off with Knight of Umbar for Fight Value stealing. Others (WK, Tainted, Betrayer, Dwimm) are the obvious no-brainer choices
If you take just 1 company Morannon Orcs, then you have 50 points for a fate - it's either "There Will Be No Dawn" for courage test re-rolls or "Doom and Despair" - for autofail. The 5c Orcs is pretty useless anyway, Fate will be much more useful.
Oh and here's something a lot of players are not aware of - when you're making a Swoop Attack, you are allowed to cast spells before landing at your final destination, so you can bombard someone with 5 Strength from Corruptions in addition to 15d3 S6 (against Courage!) attacks, and then finish far away from them
