I've got the Witchking and Narsil. I prefer Narsil, but I'm biased because when I saw the movie I just had to have it. The Witchking is a Bastard Sword IMO, it even has grips for both hands.
Narsil only has a grip for one but with the extended handle you can use two and the picture I saw had Elendil using two hands. It was probably meant to be a long sword but it's easier to use two handed, my replica is pretty well balanced.
Hope this helps. I got mine off of eBay. The auctions seem to be cheaper then the cataloges.
Both are pretty good quality. But they are not full tang, in fact my Witchking is a rat tail and the handle is slightly lose because I have to tighten it but then again I don't really plan on going into battle with it. I'll use Narsil for that.

Afterall it's so sharp that it cut the finger off the greatest Maiar in ME.

Note: None of the swords are acutally sharp.
My room-mate has Sting, Witchking, Glamdring, and Narsil, as well as Gimli's Axe which is from the Noble Collection (it's not as good as the swords IMO).
My next purchase is going to be the Ringwraith's Sword, this is a different one from the Witchking's. Also United Cutlery is going to release Aragorn's Ranger Sword and Arwen's Sword. I'm sure as more movies come out they will release more swords. I wonder if they'll make 9 different swords for each Nazgul? I bet they also will make the appearently twin swords that Legolas will use in LotR: TT.