Personally, I MUCH prefer the Trapper (16" barrel length) to the others because they are much easier to carry, easier to stow when you pack your gear, and in heavy brush or close quarters are much easier to manipulate.
For SASS use I go with the longer barrel rifles because they hold more rounds in the tube. In real life, the Trapper is IMO a better choice. The beauty of most lever rifles is that they can be "topped off" as you shoot them.
The large loop lever is purely a hollywood wanna be affectation IMO.
John Wayne used one in the movies so now...
In reality it came to be for a very practical purpose: in extremely cold conditions, you can readily fit a hand wearing a glove or mitten through the lever. The standard lever does not offer that.
In use, the loop lever will beat the stuff in's out of your trigger hand because you have to move it further to contact the far side of the loop, and then throw the lever. Wearing a mitten mitigates the hand travel and buffers the backside of your hand rapping against the far side of the lever. Certainly, its a personal choice.
Regardless of what you choose, I do believe that you will indeed enjoy it.