I've had both and I'm sticking with the Atlas.
The spring loaded legs are quick on the Harris, but can be a pain. They can fully deploy with even a quick press of the tabs. Setting the Atlas is more deliberate.
Both lock right to my rail. I did not have a QD on my Harris bipod, but with a GG&G stud mount everything was good. I did get the ADM QD mounts on my Atlas bipods. I like the tension knob setting on the Atlas. Mainly because the pod lock was another thing to get hung up on something. The pod lock I went with and would again are the items from T-Nutz. They make a nice accessory at a good price. The tension on my Atlas' have been set and I haven't touched them since. I actually like the pan ability. I find for me loading the Atlas faster and easier.
The Atlas' are to me really well made. I'm not saying the Harris isn't, just different construction and machining with the Atlas. The downside to the Atlas products are cost.
Either works, just depends what you want to spend and what "you" see as what is our works better for "you".