As Michael says, either will work well at the given ranges. Do you re-load one or the other? want to consolidate the # of calibers in the house? I would say the 30-30 with factory loads is more pleasant to shoot then the 44 loads. There are some shorter and lighter 44 mag barrels around (typically 10" octagon style) that produce uncomfortable recoil.
As always, bullet selection is important.
I think reloading is needed to really unlock the full potential of the 30-30 in a contender.
There are more 44 mag options and a contender will give you a boost over revolver performance.