I have only shot the XT so I can't compare with the LD or LX.
The XT is a very smooth, stable feeling bow in my opion. I have the 06' Allegiance with smooth cams and I would have to say that the XT has the smoother draw of the two. Very nice bow and seems to be a great shooter.
I have a switchback .I shot the xt it's a sweet shooting bow .My friend just got an ld ,he said he love's it . He had a switchback and said he like's the ld better . I had an LX it was a great shooting bow .But for me It was hot and cold . One day I would shoot light's out and the next day I'd shoot like light's off . they are both great bow's .Try to shoot them and see what you think .