I love my Goldmund linear tracker, wouldn't swap it for anything else.
Isn't that a JVC with a Rabco arm?
Just kidding - Goldmund did use JVC motors, and the Rabco was I believe a very close relative of the Goldmund arm..... I am meremly envious.

I have the series with the JVC motor since the Pabst motors were discontinued - as well as any spare parts...
I only have experience with the Rabco ST-7, and while there are similarities with my T5 arm, I wouldn say they were close relatives, more like distant cousins.
The Goldmund arm has some quirks, but once properly set up (take your time!!!) it's capable of all the good things linear arms should do and then some.![]()