Just finished my ATSA. Honestly I wouldn't recommend paying any money for a practice test/program. You get practice before the sections and, in my opinion, you either have it or you don't when it comes to stuff like memory and spatial recognition. Maybe only if this is like your last or only chance at getting the job. I felt fine with no preparation besides looking at the format at the guide here.
I felt I did fine. I think I did very well on the number difference part, the system of equations part, and the spatial recognition part. The collision part I think I did OK, but it's definitely really hard when there's eight planes at once on your screen. The math equations were pretty much impossible to answer so I just ignored most of them unless I had plenty of time. The last three parts of the test (logic/reasoning, personality, reading comprehension) were just typical as you'd expect.
Good luck to everyone.