I did it for the first time in Feb this year.   It is very challenging. I DNF'd every single stage, but had a good time and learned a lot.  Over the course, I did manage to get father in to each stage before I ran out of time so there was some improvement along the way even during the race.
Part of the learning experience was equipment selection.  Only had a red dot with no magnification on my rifle, and every rifle stage was 100 yards or further, up to 500ish.  It was like playing a video game in hard mode and then watching everyone else use an aimbot. Next time I'll have a scope. 
Also much like in other sports, where the motto is "nothing new on race day" that should apply here. 
I totally ignored that and ran 300blk instead of my normal 223/556 that I had been training on.
The terrain is also a challenge.  parts of it were very slippery and unstable so I had to balance speed with caution in some places. 
I haven't yet signed up for Oct, but probably should before all the spots get taken. :)