I purchased an AstroTrac about a year ago without any trouble, perhaps things have changed recently.
I went for the AstroTrac after some research and experimentation with other DSLR star tracking mounts. Many of the small lightweight star trackers are fine for a DSLR and lens up to about 100mm in length. I wanted to use a 200mm lens and found most were just not up to giving really good results. My nearest contender was the SkyWatcher Star Adventurer which was very convenient to use but had a large periodic error which showed up in 200mm lens shots.
The Astrotrac is expensive but you are paying for good engineering…if they still make them.