Collar vs harness is something you'll need to try and see what works best for your dog. We use a harness because I used one with a chest attachment point for the lead to train her to stop pulling and now I keep using one because no collars really come in right size that are secure and she's not that strong even if she does pull. Downside of harnesses is they can encourage pulling, plus side is your dog won't choke itself if it does. It also depends on body shape for what fits best. They both work as long as it's secure and you can control the dog if it decides it wants to go after a squirrel or run away from a truck.
Collar vs harness is something you'll need to try and see what works best for your dog. We use a harness because I used one with a chest attachment point for the lead to train her to stop pulling and now I keep using one because no collars really come in right size that are secure and she's not that strong even if she does pull. Downside of harnesses is they can encourage pulling, plus side is your dog won't choke itself if it does. It also depends on body shape for what fits best. They both work as long as it's secure and you can control the dog if it decides it wants to go after a squirrel or run away from a truck.