From the studies on both peptides along with real world info I think CJC has far more advantages and less disadvantages than GHRP-6 and Hexarelin.
As far as GH release, it is hard to compare which releses more as there is a dose dependancy. CJC, in human studies, showed increases of GH 2-10 fold after one injection, but levels rose as the effects are cumulative. Dosages there were 30-60 mcg/kg. The baseline levels of GH are drastically higher due to its long halflife. Elevated secretions of GH occur throughout the day as opposed to the injection specific timing of the other mentioned secretagogues. 1 injection will be equvelant to one peak in GH with GHRP-6/Hex.
Frequency of injections is a great positive wiht CJC over GHRP/Hex. Typical protocols for CJC are 2mg/week split into 2 X 1mg dosages.
GHRP-6 can be injected 1 to 3 times per day with varying dosages. (ex. 1 x 500mcg, 2 x 300 mcg, or even 3 x 200 mcg). For maximum GH release I hated to do 3 shots per day.
Another important detail is that GHRP/HEX and other secretagogues are NOT selective just for the pituitary somatotroph receptor. They also agonize lactotrophs and corticotrophs into producing Prolactin, and ACTH which increases cortisol. Substantial increases have been seen in studies.
CJC being a GHRH analog, acts as GHRH does, whch is on the somatotroph GHRH receptor. Studies show there was no significant increases of PRL or Cortisol in the CJC trial/study.
Hope this helps a bit.
Take Care.