Another Velocity vote here. The authentic is always a good choice, but if price is a factor and you want to go the clone route, make sure it is the Tobeco clone. Not all Velocity clones are created equal and the Tobeco is the best of the bunch.
You said you wanted something to learn and grow with and that is what the Velocity will allow you to do. The Magma is a tried and true rda, but due to it's very limited airflow, it does not leave much room for growth, or experimentation. The Velocity can do just about anything you want it to and the airflow can be set from mouth-to-lung all the way to zero restriction with everything wide open. It is a rare rda that will work just as well for beginners as it will for the advanced builder.
You said you wanted something to learn and grow with and that is what the Velocity will allow you to do. The Magma is a tried and true rda, but due to it's very limited airflow, it does not leave much room for growth, or experimentation. The Velocity can do just about anything you want it to and the airflow can be set from mouth-to-lung all the way to zero restriction with everything wide open. It is a rare rda that will work just as well for beginners as it will for the advanced builder.