Here is my two pence! 
I used to train triceps after chest and shoulders and biceps after back.
What found was my tri's and bi's were already too fucked so I was kinda just going through the motions and it wasn't intense enough.
Now I am doing arms on their own, pyramid up, the last set total failure including drop sets, then rest pause, total annihilation.
Also form is fucking imperative with arms, ever since I dropped down the weights and starting really squeezing and totally isolating the biceps it made bigger difference.
I think its all irrelevant and its just down to the juice to be totally honest, you just recover so much quicker and and blast again and the food goes straight to the muscle so you can eat more and not worry about getting fat assuming you do your cardio on top.
PS Good arms, why you don't train them direct?
I think form it the key for any exercise. You can do high reps, low reps, drop sets, pyramid sets etc. but if your form is sloppy, then you won't get results.
Nail the form and technique, and you'll grow regardless of what system you use.
I stopped training arms because I didn't like the delayed soreness that went with it. I just do plenty of chins, dips, push ups etc. Pumps the arms without causing soreness or un-comfort.
