I have a Synguider II which just works off 4 D size cells and...no need for connection to PC. It has one cable to the HEQ5 and that's it. I haven't tried it out in anger yet, but I did do a night time test without camera running and it seemed to work OK. I hooked it on to a 2.5 inch guide scope and it found stars no problem.
Only disadvantage was the TINY screen which I had to use a magnifying glass with! Biggest advantage is no need for any PHD software and memory problems when you are running the camera and the guiding all out of one laptop
No software crashes, EQMOD connections etc., completely stand alone