PATHFilmsNZ posted a nice youtube video comparing the Atlas and Harris bipods.
Personally, I had an earlier model Atlas and got rid of it. I was disappointed to find that after paying nearly three times the cost of the Harris, I had several issues.
First, the feet on the Atlas tended to roll when I pressed forward on the rifle.
Second, while the Atlas can be adjusted with the knob on the bottom, I could never get it completely locked. No matter how tight the bottom knob was, the joint always sort of flopped around.
Lastly, I bought the Atlas so I could use the legs at a 45 degree setting, however with the rifle I was using it on, the legs would collapse under the weight of the rifle. Later I was told it was a known issue, and if I wanted to, I could spend more money to have it fixed by upgrading it to the latest version. I had spent a good bit just to get the Atlas with ADM mount, spending more was not an option for me at that time.
I ended up going back to the Harris.