I think it would be fair to point out even as bias as I am toward Delta Products that all conditions being equal, i.e, damage size, skill of technician then most
professional windshield repair kits would produce good results. However, for me Delta has a produced a product that is simple to use, repairs larger chips in more locations on the windscreen than other kits and most important, has very few consumable parts. The fact it is manual also gives you the flexibility to repair cracks as your skill level improves.
Delta Kits will improve your skill level and in time you will become a better technician. Some fully automatic systems are specifically designed to put trainees into the field with one weeks training, this may sound like a good idea however, this kind of equipment has many limitations. Limitations that in time will cost you more in spare parts and lost revenue due to being unable to repair chips in certain places on the windscreen.