I own a Nemesis GT5 which is a 4.6+sightblock gun just like the Artemis. Very similar performance.
At Dragons Cup the Atlas booth had all 3 LO models available for test fire. The Artemis, Athena, and Titan all equipped with SRO.
The rep suggested I try all 3 with the CCI 115gr factory ammo. He had me shoot doubles as fast as I could pull the trigger and see where the 2nd round would land. Essentially a test to see which gun returned closer to zero with my grip pressure and that particular ammo.
The pairs were all very close with all 3 pistols and unfortunately the target had been shot out so it was the rep and another observer helping to call the hits.
The Artemis to me felt familiar due to my GT5. The Athena was impressive and felt sporty and fast. The Titan was landing my pairs very very close but it did have a noticeably different feel vs. the Athena.
I think all 3 pistols are amazing and will serve the end user well. That being said I left the booth really really liking the Athena.
Another interesting thing I learned is that with my firm grip and a sightblock, I need to run faster ammo for the return to zero characteristics of the gun to work. I run factory ammo and have already tested some faster 115s out of my GT5 with good results. So it's definitely a system between gun, ammo, and grip. I do believe there are characteristics to the gun though as far as the return to zero.