@mclaincausey:
I have the RMC USN deck jacket in olive and it is a terrific garment. It is extremely warm and one of my favorite pieces of outerwear.
If I were to buy a deck jacket today, I would go IH, only because my style has shifted a little bit away from overt militaria. Even though I haven't seen one in the flesh, my prior experiences with IH and IH outerwear and the testimonies in this forum leave no doubt as to the quality and robustness of the IH version.
I think it comes down to which design you prefer.
If you get RMC, I was surprised that for me this Japanese garment was true to size and a 40 (my real size) was a perfect fit.
If you find wool itchy, I think the RMC is pure alpaca and not a wool/alpaca blend, so that would be a better choice in that scenario.
I have no doubts about the quality of the IH jacket. Full disclosure, IH is my favorite clothing brand and I find their garments to be incredibly well made.
I guess I am more concerned with the construction quality and material choices used for the Real Mccoys version. Do you think it is very similar in terms of build quality, overall material costs, fabric weights, etc..?