I just got a STS. It takes some getting used to with the focus ring towards the middle of the scope and power adjustment ring at the eyepiece. I'm pretty sure the ATX has both rings next to eachother near the eyepiece.
Now that I'm getting used to the STS setup I've pretty much memorized where both rings are located and automatically go back and forth to each without having to remember which one is which...and exactly where they are located. The STS is a big chunk less $.
I also have a Leica spotting scope and really like having both rings close to each other rather than having to go back and forth. I'm sure you will like the focus rings on the ATX.
I believe the ATX is a little more compact for trips than having a single body plus lens (since it is modular). Some may like the option of the smaller 65 body for backpack type hunts and switch over to the 95 when weight and bulk aren't that big a deal (truck hunts). The 95 definitely lets a lot more light in...especially in low light conditions. You may want a sturdy tripod if you go with the 95x!