Alex,
I think you're asking if astrotracer works as an autoguider? I can tell you it definitely doesn't.
The astro tracer moves the sensor to follow the stars from a fixed tripod. The function won't work as a pseudo guider. You turn on the GPS, rotate the camera in 3 cartesian axes to "precision calibrate" the accelerometers. Then the camera knows which part of the sky it's pointing at. It moves the sensor in X-Y and rotationally to minimise trailing. It doesn't eliminate trailing and it doesn't guide. It's based on calculation not pixel guiding. Not perfect but not bad with fixed tripods and lenses but useless at the prime focus of a scope. That's not what it's designed for.
It has built in intervalometer, pixel shift (works like drizzle) and while it obviously works better at lower ISO, it's usable with care up to ISO 25600, Starstream (in-built image stacker for stacking star trails in-camera)
Quite a few images here were taken with my K1
http://joe-cali.com/astronomy/astrophotography-2/
The image at top of the page titled "Scorpius&Rho" is taken with Astrotrace.
If the articulating screen is really important to you, then the Pentax ticks that box. Not sure which of the other camera's have articulating screens. Just remember that you can get some cute little external hdmi video monitors that negate the need for an articulating screen.
This thread has some comparative information about the cameras.
http://www.astronomyforum.net/astro-...tax-k-1-a.html
In the end they are all very good cameras. None are bad, none are perfect. You just have to choose.
cheers
Joe