Bonding vs Veneers/crown? Which option would be the best for the long term? How strong is dental bonding on a front tooth?

Dental bonding will not last as long as a porcelain veneer or 3/4 crown, and when the bonding fails it may lead to further destruction or tooth loss.  Often, the intent to do bonding first and a veneer or crown later if needed gets negated when the failure of the bonding leads to loss of the tooth, or the need for a root canal as well.  The dental bonding option should be considered as a temporary fix and the 3/4 crown a much longer lasting option.  

Often, the personal demands or expectations exceed what bonding can offer, and while bonding can be done initially with the intent to do it over if needed, patients lose faith in the ability of the doctor (assuming that if the bonding didn't work, it was due to the poor skills of the doctor).

Sometimes it is best to do it right the first time.

Bonding is a more temporary restoration but can be a cost effective method of quick restoration.  It is very conservative but can look terrific.  Over time it will discolor but the materials have gotten better over the years.  Getting a perfect color match on a single veneer can be challenging while direct bonding is easier to match.Veneers, 3/4 crowns and 360 degree veneer crowns all restore the tooth in a more permanent fashion.Ideally you would like to bond to enamel not dentin.  Preserving enamel is the key to a long lasting restoration.  When there is a great deal of discoloration it is sometimes necessary to remove more tooth structure.  This sacrifices some strength for esthetics.

I believe that you would be better off with a porcelain veneer or crown as opposed to dental bonding due to the amount of tooth structure that you are missing.  Dental bonding is a good treatment option  for small chips, but not for teeth missing considerable tooth structure.  Porcelain is much stronger and will have a much longer life span than the bonding.  In addition, the color match will be much better with porcelain.