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Ok, a little lesson in VTEC, and why it's important (and why it's impressive) is in order.
To start with, you need to know a bit about how a typical 4 stroke internal combustion engine works, so you know what a cam is, and what the valves do. If you don't know, check out howstuffworks.com, then come back.
The camshaft(s) open and close the valves in an engine, based on their lobe shape (the lobe is kind of round, but looks a bit like an egg if viewed from the side) much of it's diameter it's a circle, but for a bit it gets taller, which opens the valve. How tall it gets, and how long it stays there is a large part of what determines how much power the engine make and where that power is made. A typical stock engine had a medium amount of valve lift, and a medium amount of valve opening duration, very little overlap between the intake and exhaust valves being open, and a specific point in the combustion process the valves open AT.
A performance engine might have more lift, a bit more duration, and a bit more overlap, as well as a different RATE of lift. Where you want the power made (and remember, that's determined by torque and rpms) determines the exact shape and position of those lobes on the camshaft.
Too much lift and duration for a particular engine combination, and you might get goot high end power, but be unable to even RUN at low rpms. This is fine for a pure race car, especially a darg car, but not too good for a street car. On the other hand, too mild a lobe profile and you get great around town driveability and low end power, but it runs out of breath pretty quick, and won't rev very far. Great for a street engine but pretty sucky for a race or performance engine.
In the past, REGARDLESS of type of car (be it a BMW 2002 Ti, an air cooled VW, a small block V8 Mustang, or a big block Chevy) you had to balance your specific needs and engine components to determine the optimum cam shape. If you wanted a mostly race car, you compromised towards upper rpm power, but lost street driveability. If you wanted arond town grunt, you wouldn't rev very far. It was always, ALWAYS a compromise. Larger engines less so, as you could still make enough low rpm power to compensate purely from displacement, but for the average sport sedan and traditional sports car with a small engine, nothing dual purpose was EVER a perfect match. And it is a serious pain to install a street cam grind to drive around, then install a race cam on teh weekends to go racing. And you couldn't do it on the fly when you simply wanted a bit of fun. If you put a race cam with a non race intake manifold and carb, you were screwed. Same if you left a street cam in with a race intake and carb setup (like, say, a tunnel ram on an old Chevelle)
Early on, engine builders learned that you could take a slightly tuned cam and adjust the timing a bit advanced to make a bit more power. It wasn't much, but it was easier than swapping cams. Alfa and Porsche put a system in their cars that adjusted teh cams slightly based on rpm to advance it a bit for more power when needed. it wasn't much, again, but it WAS automatic. Soon you could buy kits for it for other small cars. But most engine builders simply picked the best compromise for the intended use, and left it at that.
But then, after a number of years, Honda came along with an absolutely INGENIOUS invention: VTEC. While it stands for Variable Timing and Electronic Control, it was MUCH more. Honda put two separate lobe shapes on each cam, and then mechanically switched between them on the fly at a certain rpm. Not only was the timing of the cam lobe in relation tothe crank changed (by having it operate at a slightly different degree on the camshaft itself), with the change in lobe cam a change in lift, duration, and overlap!
What this meant was that for the first time, you were esentially driving around on a stock street cam around town, but when you wanted to go for it, essentially a mechanic automatically installed a high rpm race cam while you were driving! And installed the stocker back in it when you slowed down. Unhead of! And it took nearly 10 years for anyone to come close to matching it. Variable valve timing is NOT the same! VANOS, Double VANOS, all those are NOT the same. VVTi-L is the very nearly the only one, and it arrived nearly 10 years after VTEC.
With one shot, Honda reinvented the sport sedan and sports car engine.
While the upper rpm cam was no different or no more powerful than any race cam had ever been in an engine, the important thing was that unlike a race cam engine, the Honda system gave back lost low end power and driveability.
ALL small race and performance engines revved good, and made power up high. And still do. ONLY Honda VTEC engies did so while retaining smooth daily driveability when NOT "on the cam." People who say VTEC cars have no low end are kidding themselves, or simply ignorant of how performance engines have always been. The same engine without VTEC would not only haev LESS low end, but very likely couldn't idle at all (or would idle at 2000+ rpm!) and would be very hard top get off the line without either stalling or spinning the tires from dumping the clutch at higher rpms.
VTEC allowed economy cars to economical ability without losing performance capability. VTEC allowed sports cars to have performance engines without losing daily driveability. No one else had done it, and everyone wants it now.
Hell, those of us that used to build fast V8 cars in the '60s and '70s would have LOVED the ability to have our performance cams and daily driveability at the same time! If I could have in a small block Chevy the higher rpm power of a Comp Cams 260/555 (3000-7000 rpm) and the daily driveability of a Comp Cams 224/470 (1500-5800 rpm) in the same engine at the same time, it would have been pure magic!
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