Guard is near worthless. I severely doubt you can guard while asleep/stunned/terrored, seeing as how no defensive skill bar-evasion will proc. That's if you can get Guard to proc in the first place.... I evade more with my C evasion on PLD than a MNK guards.

Blocking negates spell interruption, guarding does not.

Blocking negates more dmg than guard.

Blocking grants more TP than guarding via Shield Mastery.

Even without including something like Ochain or reprisal into your little equation, Shield > Guard.

Also: Perfect Counter only counters 1 attack, not 3.