It is tough to compare.
I use Folligen every other day, currently. I use it for it has the highest amount of "peptide chains," and is supposedly better (per the creator of both Tricomin and Folligen.) He may be saying this for he had a split with Procyte though.
I have used Tricomin occasionally in the past. I like using Tricomin (and probably will use it again sometime) for it has specific "peptides," targeted at scalp problems. Bryan used to prefer Tricomin vs. Folligen due to this reason. Maybe he still does. Plus, they went through a few phases of FDA trials as support. It is also easy to apply in the morning without evidence you have stuff on your head.
I have never used Prox-N. I am actually interested in using it, due to its many synergisitc agents, including additional growth stimulators. Depending on the concentrations of the active ingredients and their stability when mixed together, this may be the best choice for many.
I like to rotate as part of my regimen, so I will probably use all at some time. I think they all have benefits. How much is the reason we all report here. I hope these all work for everyone.
--Fuzz