just from my own experience
i used the arginine/ornithine combo in my 20's to good effect. it stripped the BF and increased vascularity quite well.
this without having to change my WO routine.
as new products have come along lately i tried a few but for the price none could compete with real GH.
a study i read (i don't have the link right now) stated that GH releasers tend to lose their effecacy the older you get. this would explain why they worked well in my 20's not so well in my 40's.
likewise i find the rules for their use (the timing, the no food for x amount of hours before or after) to be more of a bother than they are worth when they don't work that well.
your mileage may vary, but for my money nothing yet beats the real deal.