I have heard this more than a few times, usually from Canadian sources and usually in connection with the battle of Vimy Ridge. To my knowledge, the Germans thought nothing special of Canadian soldiers.

The German post battle analysis of Vimy ridge was rather extensive but the conclusion was that the staff had ignored frontline commander warnings, that the defense had been too rigid and that reserves were too far back to effectively counter-attack. No mention at all was made about the Canadian troops preforming any differently from other allied troops.

Despite it's importance to Canadians the battle is often grosly over-stated in importance, especially in Canada. The Germans did not consider Vimy Ridge a serious loss, they viewed it as more of a stalemate since no breakthrough occurred and no follow-up came.

By WW2 we have a somewhat clearer picture of what the germans thought of commonwealth and us soldiers but again, the Canadians do not stand out. Ghurkas were notably feared by German veterans from Italy. Siberian riflemen and Guards rifles were feared/respected by eastern front veterans.

In general the Germans considered western allies to be overly cautious and lacking in aggression. They thought allied commanders often lacked a clear picture of when an objective could be taken and the aggression to push hard enough for that objective. The also thought the coordination between armor and infantry was generally poor, especially in the first months after the US landings in Italy and Africa.

The Germans saw the strengths of the allies too of course. The extremely heavy and accurate use of artillery. The swiftness of allied fire and air support etc but again, nothing about Canadians troops in particular.

"The German Army at Vimy Ridge" Hayes, G. 2007

"Constructing Memory: The Vimy Memorial" Pierce, J. 1992

"What Jerry Thinks of Us... and Himself" from Intelligence Bulletin, Dec. 1944 (WW2 opinions)

With regards to WWI, John Terraine recounts that

It was a well-established fact that when either the Australians or the Canadians appeared in a sector trouble was brewing. This was particularly true of the Canadians because of their Government’s rigid insistence that their divisions should never be separated. It was, therefore, necessary not only to hide completely the presence of this Corps, 100,000 strong, which would have to be in the front-line at zero hour, but also to hide the fact that it was no longer in the sector, far to the North, where the Germans would already have identified it.

The Canadian Corps was the largest single cohesive fighting unit in the entire BEF - what's more it was experienced as a unit. Most other Corps were fairly amorphous. Brigades and battalions would come and go, but the Canadian Corps was maintained intact from Vimy through to the end. This engendered a better degree of trust and cooperation between staff and fighting officers, and between the officers of the different subordinate formations, and thus ensued improved efficiency and efficacy overall.

What's more the Canadian Corps was unusually large (at around 100,000 men, it could field more fighting troops than today's British and Canadian armies combined). This was because the Canadians were able to resist the cutting down of Brigades from 4 to 3 Battalions, and maintaining 4 active Divisions in the Corps instead of 3.

So yes, its no exaggeration to say they were viewed and used as 'Shock Troops' in WWI due to the Canadian Corps' superior organisation and structure.

HOWEVER - it was not only Canadian or ANZAC outfits that were capable of great feats of arms. Arguably the most astonishing successes of the entire war was the breaching of the Hindenburg line by the St Quentin canal by the 46th (Territorial) Division - a thoroughly ordinary British infantry Division that had up to that time completely distinguished itself only by its bloody failure to take the Hohenzollern Redoubt after Loos in 1915.

This emphasizes and important point: That the success of the BEF in 1918 was not down to a few elite units, but to the overall proficiency and fighting skill of the army in its entirety.

With regards to the perception of Vimy in Canada, yes it is overstated. the Dominions viewed their participation in WWI has somehow signifying their emergence as fully fledged independent states.

I am not sure what the logic is behind this line of reasoning, but it certainly seems to exist (reference the visitors centre at Vimy, for example).

There is also a perception among what were the Dominions that their troops somehow constituted an elite force within the British armies as a whole. While this is partly due to nationalist conceit, its also partly true.

British troops were drawn from a population in which most men of fighting age were either office workers or lived in rural slums or urban squalor with widespread nutritional defiencies such as ricketts. The Dominion troops were more likely to be of better physical character, being ranchers, frontiersmen and so on and were therefore better material for combat. The Canadians in particular benefitted from being under Sir Julian Byng, arguably the best General, rank for rank, of the war.

However, the German take on Vimy is also sheer humbug. Pretending it was a minor loss of a few hundred meters of some insignificant ground just doesn't ring true.

Dispatching your number one trouble-shooter with plenipotentiary powers, ordering a Supreme Army Command court of enquiry into the matter, and sacking a full army commander are the real indications of how seriously the matter was viewed.

What's more, none who have stood atop Vimy ridge and seen the ruins of Mont St. Elois to the east and the mine dumps of Lens, like grim pyramids, on the vast and sprawling plains to the west, can reasonably deny the immense strategic significance of the location.