Have never used a versa pod. I did have the opportunity to compare a Harris to my Atlas this past fall.
Having owned the Atlas for awhile I will say right off that I am biased towards it.
At around $280 for the QD model it isn't cheap. However being QD you can move it from gun to gun easily and quickly. Do I need this expensive of a pod.....? Absolutely not. In fact it's probably overkill to the max for my uses. On the other hand, it does have some features that I really like and do use.
I'd give the nod to the Harris as far as quick initial deployment. Once past this phase of use, IMO the Atlas shines head and shoulders above the rest. Note that most of my uses don't require me to be lightning fast deploying the pod.
A big plus IMO is the ability to lock the Atlas legs at different angles depending on needs - staight down, forward or towards the rear. You can also easliy add 3" leg extensions if you wish/need too as well as change out the feet if your needs dictate.
Does the Harris work well on my brother's rifle.....? Yup, sure does. Would I buy one? No. If I need another bipod, I'll get another Atlas without a second thought. It's absolutelty overkill I know, but the features and the degree to which it's built over and above my uses, providing a huge margin of confidence in use.
I imagine it's sort of like looking through and testing some of the uber high end glass. Once you've been there, you can go back down to lesser levels. It still works, but...........
I have no reqrets buying the QD Atlas. If I ever need another, I'll buy one, but hopefully having the QD model will prevent that for awhile.