It is his opinion and while I would disagree with his statements there is some truth in it as traditionally Commandos are a strategic force and not really meant to be used as a conventional force (likewise with the Para's really).
I think he lacks the understanding of what a marine commando can actually do, in Afghansitan the Army regulars,Para's,Raf and Royal Marines (both commando and bandy) could be very much on par with combat experience whilst being used as conventional forces...but if all support was lost (no helicopters, artillery etc) the Marine Commandos and Paratroopers would upstage any other Soldier in the British/Coalition forces.
Just finished reading a book on the Falklands and it truly shows what the difference in training does, Marine Commandos & Paras ,had little food,water, clothing, ammunition (at times) or transport and just got on with the job where as the conventional troops of the Welsh and Scots guard had difficulty moving across the land scape and dealing with lack of support and by the quotes from the commanders of the forces they were a shamble at times (still did dam fine job mind you)
As for the USMC comment, I don't know entirely where that would come from, Royal Marine Officers do exercises with the USMC and from books i have read there have been many instances where USMC and Royals have served and trained together. Along with marines i have spoken to they all respect most of the USMC and say they regard the Royals are the best there is.
