What`s the difference between the Johnson and Johnson vaccine and the others ?

The ultimate difference is the way the instructions are delivered. The Moderna and Pfizer vaccines use mRNA technology, and the Johnson & Johnson vaccine uses the more traditional virus-based technology.
Instead of using mRNA, the Johnson & Johnson vaccine uses a disabled adenovirus to deliver the instructions. This adenovirus is in no way related to the coronavirus. It is a completely different virus. Although it can deliver the instructions on how to defeat the coronavirus, it can’t replicate in your body and will not give you a viral infection.
Are there benefits to the Johnson & Johnson vaccine, based on its technology?
Absolutely. The huge advantage to the Johnson & Johnson vaccine is that it is a single shot. The mRNA vaccine requires two.
72% effective 85% in preventing hospitalization and death.