My cats just have a collar and leash set up, no harnesses. My cats are generally well behaved cats so they don't try and squirm free or anything so I never went with the full harness. I think mine are just so excited to be outside, they don't care about anything else!
Mine have actually started to get very excited now, and they know they go outside when they get the leash put on, so whenever I put the leashes on them in the house they go insane!Mine for some reason love the snow, they roll about and jump and play in it! I think sometimes in the summer it gets too hot for them as they are very very furry.