If it wasn't clear from my post, I actually liked the fact that it didn't "lock". It allowed me to make minor adjustments to correct the cant that inevitably creeps in when shooting from grass/dirt/gravel surfaces on various firing lines. As far as movement, obviously the better your position behind the rifle, the more straight back it will recoil, and the less hop and lateral movement you will see. That is true regardless of the type bipod you're using. The footprint on the Atlas is comparable to the Harris, maybe just a tick wider. As such, you can/will get some lateral movement when using it if you're not straight behind the rifle. It's not at all unmanageable, but it's definitely there if you don't drive it correctly. A bipod with a wider footprint will lessen that to some degree, although not entirely. Probably a fair degree of it is personal preference, but I've shot some pretty decent MR and LR scores using an Atlas, so for me it definitely worked. As I stated earlier, I do prefer the wider stance of the LRA bipod I'm currently using, but it's not a really huge difference, just a small step up for how I like to shoot.
Again, if lateral movement is a big concern, one of the [very] wide sled-type bipods can provide a really stable platform, but there are issues that come with them including extra weight (compared to something like the Atlas), ease of adjustment while shooting, and the fact that they aren't going to be as useful for other types of shooting comps (tactical, for example); they're really designed specifically for F-T/R. I currently have a Duplin Rifles bipod that I'm "learning" to use. Basically, I haven't yet decided whether I like shooting with that style of bipod enough to use it in a competition. Because of the angled buttstock bottom on the A5 stocks I have, most of the rear bag adjustments used during shooting are exactly the opposite of what I do with a standard-type loaded bipod/rear bag setup, so learning to use it properly without loading is taking a bit of getting used to. Overall, I would say the type bipod one uses is probably not going to be the limiting factor for most. For that reason, I think it's possible to do quite well with several different types of bipods, as long as you have a solid setup, a good load for it, and know something about reading the wind conditions. Frankly, there are lots of people that will spend tons of money and huge amounts of time tweaking this or that, or getting this or that piece of new gear, while neglecting to learn good wind reading skills. IMO many more points are lost to bad wind calls than all other sources combined, so getting a solid bipod is a good idea, but not the overriding concern. As long as you're comfortable with it, you can then focus your attention on other more important issues like making good wind calls.