Thats actually a pretty good question, my experience using it so far has been relatively easy and stress free.
I guess 1 thing that threw me in the very beginning was that I had no idea how to achieve things like comparing "Distance(player.x, player.y, enemy.x enemy.y)". I had to copy and paste it from another tutorial cap.x into my project.
There is a nice tutorial on system expressions though it could be noobified a little.
Oh and by the way you can edit your post by clicking post options - and then edit. Lol i make spelling errors all the time :)