Musicians

Get an idea for they way each of the necks feel and the action on the guitars and how they sound. I can tell you with certainty if you buy any guitar without playing it first you'll come to regret that decision.

Also, what type of music will you be playing. The Gibson J-45 is going to have a very different sound than the other guitars you have listed. It tends to have a fuller base sound than even a more similar Martin D-18 or D-28. Mahogany tops like the other four options tend to have a brighter sound. Of the ones you have listed, I personally love the J-45, but that's just me. That being said, I own a Martin D18 and it's my favorite acoustic, largely because you can see the care that went in to making it and it just sounds so good.