In my opinion, I'd say that Taranto was an early Pearl Harbor. The Japanese studied the raid and learnt it's lessons. However, the failure of the US to take in the lessons was one of the biggest military blunders of the war which would lead to tragedy for the US Pacific fleet. Cunningham's raid on Taranto proved that it was possible to mount an airborne torpedo attack on a fleet in port.
A night attack by a squadron of planes targetted at ships is a very different story from a massed attack aimed at knocking out a whole base. The FAA Swordfish had performed numerous attacks on Italian bases before that, IMO Supermarina's failure to predict Taranto was worse than the USN to predict PA (thinking out of the box is not a common military trait).
What the British managed to do with ONE aircraft carrier attack at Taranto was, IMHO, a more efficient and devastating blow to an enemy's naval capabilities than the Japanese at Pearl Harbor. With ELEVEN (the other ten Swordfish in the attack carried light bombs and/or flares) torpedo-bombers, flying through a WARNED and READY air defence, past barrage balloons and anti-torpedo nets, the British managed to put THREE Italian battleships on the bottom of the harbor. One never sailed to war again. That attack disabled HALF of the Italian battlefleet! TOS--the Japanese were not trying to "knock out Pearl Harbor as a base", just the ships, and the defensive air components that might oppose the attack on the ships. Supermarina, too, had "defended" Taranto MUCH better than the Americans did at Pearl. Anti-torpedo nets, barrage balloons (neither one used at Pearl), searchlights and AA sites were a reasonable defense. The Italians had ample warning of the coming attack and were nominally ready. Italy and Britain, however, were decidedly already AT WAR, so there was no question of *IF*. So the Japanese also disabled half of the American battlefleet, but it took them SIX carriers with some six times the number of torpedo-bombers, and did about three times the damage. My hat is off to Andrew Cunningham (named my first son after him!), the Illustrious, and the "Stringbag warriors" of the Fleet Air Arm!
My hat is off to Andrew Cunningham (named my first son after him!) Now that deserves a salute on its own merit....Thank god Sosabowski was not an admiral.