even though they are essentialy the same, each one dose have it's flaws for example:
vtec has very little torque.
VVL parts are rare and hard to come by.
VTC only works on the intake cam.
nissan guy: *coughs* no torque *coughs*
ford guy: you know he's right
Honda and Nissan guy: shut up, you car doesn't even run.
VTEC keeps the hamsters from getting too tired.
Wait, you mean a bottle of Mountain Dew displaces more than my engine?