Whether Veneers or Orthodontic procedures are the solution for you depends on many factors.
Are you concerned with the gap between the teeth only or also the protrusion of the teeth? If you have protruded teeth, it may be more appropriate for the teeth position to be corrected with orthodontics. And by correcting the protrusion, chances are that the gap will close naturally.
Whether you can close the gap between the teeth - without correcting the position -- will depend on the size of the gap relative to the width of your teeth. If the gap is large, then closing the gap with Veneers, or by Bonding, may make your teeth look exceptionally large.
Orthodontic treatment may take longer but the procedure is conservative i.e. there is no cutting of tooth structure. Veneers to correct protrusion of teeth may be quite invasive.
You do need to have a clinical examination where the cause of the gap and the relative positions of your teeth can be assessed before your dentist can walk you through the treatment options, the expected results, the pros and cons, and of course the costs involved.
Ultimately, the treatment you choose will depend on your desired objectives.
