I have both and maintain both. I ran Harris for years and then picked up my Atlas when I moved to the AICS stock. I now switch back and fourth, more on whim, trying to make up my mind on what way to go for the rest of my rifles. I slightly prefer the Atlas over the Harris, not by a huge margin, but enough for me to justify the extra cost. However, if money is an issue and you have less disposable income then stick to the Harris "S" series and don't look back. What I like about the Atlas over the Harris is the position of the legs. I like to get low when I shoot and the forward position of the Atlas allows me to get a very low position. A few times I have deployed on very uneven ground and needed to use the independent legs to get into position so that is also a plus. As far as quality, I call it a wash. Sure gear breaks, fact of life, but there is nothing to indicate a flaw in either design and I am sure you could field 1000 of each and 20 would break under some condition or another. So if you already run a Harris then use it till it breaks and then try the Atlas and if you don't like it you can flip it here on the hide. I just see no reason to see off what your using to try the Atlas, unless of course you can afford it. In the the case of the OP if your buying from scratch I would say the Harris and that is because in the opining post you brought up the cost. Had you said that "money is no object" then by all means go with the Atlas.
Sully