I do power and clutch wheelies.
Power Wheelie
Pros: Comes up gracefully, sounds and looks bad ***, need a light bike and/or a powerful bike (best on dirt bikes IMHO).
Cons: Can't do it on your motorcycle with a lawnmower engine.
Clutch wheelie
Pros: Comes up fast, once you get it down pat... You can pull it up/ride them out in most if not all gears. All bikes can clutch wheelie including your bike equipped with lawn mower engine.
Cons: comes up fast (cover the rear and you're in the clear), you can flip it with too much throttle, you can kill your clutch over time.
Nasty on your forks, especially if you've left them at the soft, spongey, stock settings...
Anyone can wheelie, but it's not for everyone... The wheelie machine is unnecessary and it won't help you at all. It's for turds who haven't hopped on a bike before. Be safe!