I took the test this morning and passed with an 85% on the first attempt. It took me 3 hours and 20 minutes, with some distractions in between.
A few notes...
1) I would recommend you have an electronic copy of the standard, if you are in the panel shop program you can get an electronic copy free. This allows you to CTRL+F the standard to find things quicker.
2)Make sure you have time allotted to analyze the questions and come up with the best answer, I am not a seasoned vet to 508A but not a noob either, and I found the test pretty challenging.
3) As pointed out before make sure you are up to date on SCCR calculations and the like. Specifically, fuses on the feeder circuits and how peak let through plays into SCCR. Also make sure you are aware of how transformers play into SCCR.
There is a course for free on UL right now that basically is the webinar version of the in person instruction. There are module that you can do to brush up on certain areas, you dont have to do the whole thing. To be completely honest, I dont think I would have passed on the first attempt without first reviewing a few of those course modules.
I guess in final thoughts, dont disregard it as a red tape requirement, it was a challenging test.