I went with the Tracker II instead of the Ultra Slug for two reasons, weight and cost.
I do all my own gunsmiting, so there was no cost associated with the drill and tap for the scope mounting, so for a grand total expenditure of $136, I had a scoped slug gun ready to go (I already had the scope).
Shoots as good as I can expect a slug gun to shoot (<2" groups at 100 yards).