Enough of these opinions. I made a simple map of 10 archons vs 15 guardians. I spread out the guardians to simulate "micro". 5 archons died versus 15 guardians annihilated.
www.boomspeed.com/jake/guardsvsarchons.rep
Owned.
BTW 500 minerals, 1500 gas was used for protoss team.
Compared to 2250 gas and 3000 gas used for the zerg team.
Yes you're right, guardians have range. But 5 archon hits kill 1 guardian. Versus approximately 18 hits to kill one archon.
Edit:
I got curious and see how far 10 archons could go.
10 mutas, 10 hydras, about 3 dozen zerglings, one ultralisk.
www.boomspeed.com/jake/archonsvszerg.rep
3 archons were left. Again, I did not micro my archons. I let the ultralisk attack from the flank.