Ever used a harness for your dog?

I took my 10 year old Aussie to the vet the other day, she was gagging and having a hard time eating. I was so afraid it was leukemia... that's what my last dog had, and I remember her having similar issues. He said it was not that, but a soft palate problem.

He suggested using a harness on her, instead of a collar.

I need one that can be worn all the time, and is easy to hook a leash up to. The place the leash snaps on would need to be on the top, not at the front of the dog like I have seen on some harnesses on line.

I looked at pages of links google found for dog harnesses. There are a lot of styles!

I am clueless about harnesses. Have never used one before on a dog.

Any suggestions or types you can recommend?

Thanks!